Method and system for detecting objects external to a vehicle

ABSTRACT

Method and system for obtaining information about objects in the environment outside of and around a vehicle and preventing collisions involving the vehicle includes directing a laser beam from the vehicle into the environment, receiving from an object in the path of the laser beam a reflection of the laser beam at a location on the vehicle, and analyzing the received laser beam reflections to obtain information about the object from which the laser beam is being reflected. Analysis of the laser beam reflections preferably entails range gating the received laser beam reflections to limit analysis of the received laser beam reflections to only those received from an object within a defined (distance) range such that objects at distances within the range are isolated from surrounding objects.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/822,445 filed Apr. 12, 2004, now U.S. Pat. No. 7,085,637,which is a continuation-in-part of:

1) U.S. patent application Ser. No. 10/118,858 filed Apr. 9, 2002, nowU.S. Pat. No. 6,720,920, which is:

-   -   A) a continuation-in-part of U.S. patent application Ser. No.        09/177,041 filed Oct. 22, 1998, now U.S. Pat. No. 6,370,475,        which claims priority under 35 U.S.C. §119(e) of U.S.        provisional patent application Ser. No. 60/062,729 filed Oct.        22, 1997;    -   B) a continuation-in-part of U.S. patent application Ser. No.        09/679,317 filed Oct. 4, 2000, now U.S. Pat. No. 6,405,132,        which is a continuation-in-part of U.S. patent application Ser.        No. 09/523,559 filed Mar. 10, 2000, now abandoned, which claims        priority under 35 U.S.C. §119(e) of U.S. provisional patent        application Ser. No. 60/123,882 filed Mar. 11, 1999, and which        is a continuation-in-part of U.S. patent application Ser. No.        09/177,041 filed Oct. 22, 1998, now U.S. Pat. No. 6,370,475,        which claims priority under 35 U.S.C. §119(e) of U.S.        provisional patent application Ser. No. 60/062,729 filed Oct.        22, 1997; and    -   C) a continuation-in-part of U.S. patent application Ser. No.        09/909,466 filed Jul. 19, 2001, now U.S. Pat. No. 6,526,352; and

2) U.S. patent application Ser. No. 10/216,633 filed Aug. 9, 2002, nowU.S. Pat. No. 6,768,944, which is a continuation-in-part of U.S. patentapplication Ser. No. 10/118,858 filed Apr. 9, 2002, now U.S. Pat. No.6,720,920.

All of the above applications are incorporated by reference herein.

FIELD OF THE INVENTION

This invention is in the fields of automobile safety, intelligenthighway safety systems, accident avoidance, accident elimination,collision avoidance, blind spot detection, anticipatory sensing,automatic vehicle control, intelligent cruise control, vehiclenavigation, vehicle-to-vehicle communication, vehicle-to-non-vehiclecommunication and non-vehicle-to-vehicle communication and otherautomobile, truck and train safety, navigation, communication andcontrol related fields.

The invention relates generally to methods for vehicle-to-vehiclecommunication and communication between a vehicle and non-vehicles andmore particularly to apparatus and methods using coded spread spectrum,ultrawideband, noise radar or similar technologies. The coding schemecan use may be implemented using multiple access communication methodsanalogous to frequency division multiple access (FDMA), time divisionmultiple access (TDMA), or code division multiple access (CDMA) in amanner to permit simultaneous communication with and between multiplevehicles generally without the use of a carrier frequency.

The invention also relates generally to an apparatus and method forprecisely determining the location and orientation of a host vehicleoperating on a roadway and location of multiple moving or fixedobstacles that represent potential collision hazards with the hostvehicle to thereby eliminate collisions with such hazards. In the earlystages of implementation of the apparatus and method and when collisionswith such hazards cannot be eliminated, the apparatus and method willgenerate warning signals and possibly initiate avoidance maneuvers tominimize the probability of a collision and the consequences thereof.More particularly, the invention relates to the use of a GlobalPositioning System (“GPS”), differential GPS (“DGPS”), otherinfrastructure-based location aids, cameras, radar, laser radar,terahertz radar and an inertial navigation system as the primary hostvehicle and target locating system with centimeter level accuracy. Theinvention is further supplemented by a processor to detect, recognizeand track all relevant potential obstacles, including other vehicles,pedestrians, animals, and other objects on or near the roadway. Moreparticularly, the invention further relates to the use ofcentimeter-accurate maps for determining the location of the hostvehicle and obstacles on or adjacent the roadway. Even moreparticularly, the invention further relates to an inter-vehicle andvehicle-to-infrastructure communication systems for transmitting GPS orDGPS position data, velocities, headings, as well as relevant targetdata to other vehicles for information and control action. The presentinvention still further relates to the use of Kalman filters, neuralnetworks, combination neural networks and neural-fuzzy rule sets oralgorithms for recognizing and categorizing obstacles and generating anddeveloping optimal avoidance maneuvers where necessary.

BACKGROUND OF THE INVENTION

All of the patents, patent applications, technical papers and otherreferences referenced below are incorporated herein by reference intheir entirety. Various patents, patent applications, patentpublications and other published documents are discussed below asbackground of the invention. No admission is made that any or all ofthese references are prior art and indeed, it is contemplated that theymay not be available as prior art when interpreting 35 U.S.C. §102 inconsideration of the claims of the present application.

There are numerous components described and disclosed herein. Manycombinations of these components are described but to conserve space,the inventors have not described all combinations and permutations ofthese components but the inventors intend that each such combination andpermutation is an invention to be considered disclosed by thisdisclosure. The inventors further intend to file continuation andcontinuation-in-part applications to cover many of these combinationsand permutations.

Automobile accidents are one of the most serious problems facing societytoday, both in terms of deaths and injuries, and in financial lossessuffered as a result of accidents. The suffering caused by death orinjury from such accidents is immense. The costs related to medicaltreatment, permanent injury to accident victims and the resulting lossof employment opportunities, and financial losses resulting from damageto property involved in such accidents are staggering. Providing theimproved systems and methods to eventually eliminate these deaths,injuries and other losses deserves the highest priority. The increase inpopulation and use of automobiles worldwide with the concomitantincreased congestion on roadways makes development of systems forcollision avoidance and elimination even more urgent. While manyadvances have been made in vehicle safety, including, for example, theuse of seatbelts, airbags and safer automobile structures, much room forimprovement exists in automotive safety and accident prevention systems.

There are two major efforts underway that will significantly affect thedesign of automobiles and highways. The first is involved withpreventing deaths and serious injuries from automobile accidents. Thesecond involves the attempt to reduce the congestion on highways. In thefirst case, there are approximately forty two thousand (42,000) peoplekilled each year in the United States by automobile accidents andanother several hundred thousand are seriously injured. In the secondcase, hundreds of millions of man-hours are wasted every year by peoplestuck in traffic jams on the world's roadways. There have been manyattempts to solve both of these problems; however, no single solutionhas been able to do so.

When a person begins a trip using an automobile, he or she first entersthe vehicle and begins to drive, first out of a parking space and thentypically onto a local or city road and then onto a highway. In leavingthe parking space, he or she may be at risk from an impact of a vehicletraveling on the road. The driver must check his or her mirrors to avoidsuch an event and several electronic sensing systems have been proposedwhich would warn the driver that a collision is possible. Once on thelocal road, the driver is at risk of being impacted from the front, sideand rear, and electronic sensors are under development to warn thedriver of such possibilities. Similarly, the driver may run into apedestrian, bicyclist, deer or other movable object and various sensorsare under development that will warn the driver of these potentialevents. These various sensors include radar, optical, terahertz or otherelectromagnetic frequencies, infrared, ultrasonic, and a variety ofother sensors, each of which attempts to solve a particular potentialcollision event. It is important to note that as yet, in none of thesecases is there sufficient confidence in the decision that the control ofthe vehicle is taken away from the driver. Thus, action by the driver isstill invariably required.

In some proposed future Intelligent Transportation System (ITS) designs,hardware of various types is embedded into the highway and sensors whichsense this hardware are placed onto the vehicle so that it can beaccurately guided along a lane of the highway. In various other systems,cameras are used to track lane markings or other visual images to keepthe vehicle in its lane. However, for successful ITS, additionalinformation is needed by the driver, or the vehicle control system, totake into account weather, road conditions, congestion etc., whichtypically involves additional electronic hardware located on orassociated with the highway as well as the vehicle. From thisdiscussion, it is obvious that a significant number of new electronicsystems are planned for installation ontovehicles. However, to date, noproduct has been proposed or designed which combines all of therequirements into a single electronic system. This is one of the intentsof some embodiments of this invention.

The safe operation of a vehicle can be viewed as a process in theengineering sense. To achieve safe operation, first the process must bedesigned and then a vehicle control system must be designed to implementthe process. The goal of a process designer is to design the process sothat it does not fail. The fact that so many people are being seriouslyinjured and killed in traffic accidents and the fact that so much timeis being wasted in traffic congestion is proof that the current processis not working and requires a major redesign. To design this newprocess, the information required by the process must be identified, thesource of that information determined and the process designed so thatthe sources of information can communicate effectively with the user ofthe information, which will most often be a vehicle control system.Finally, the process must have feedback that self-corrects the processwhen it is tending toward failure.

Although it is technologically feasible, it is probably sociallyunacceptable at this time for a vehicle safety system to totally controlthe vehicle. An underlying premise of embodiments of this invention,therefore, is that people will continue to operate their vehicle andcontrol of the vehicle will only be seized by the control system whensuch an action is required to avoid an accident or when such control isneeded for the orderly movement of vehicles through potentiallycongested areas on a roadway. When this happens, the vehicle operatorwill be notified and given the choice of exiting the road at the nextopportunity. In some cases, especially when this invention is firstimplemented on a trial basis, control will not be taken away from thevehicle operator but a warning system will alert the driver of apotential collision, road departure or other infraction.

Let us consider several scenarios and what information is required forthe vehicle control process to prevent accidents. In one case, a driveris proceeding down a country road and falls asleep and the vehiclebegins to leave the road, perhaps heading toward a tree. In this case,the control system would need to know that the vehicle was about toleave the road and for that, it must know the position of the vehiclerelative to the road. One method of accomplishing this would be to placea wire down the center of the road and to place sensors within thevehicle to sense the position of the wire relative to the vehicle, orvice versa. An alternate approach would be for the vehicle to knowexactly where it is on the surface of the earth and to also know exactlywhere the edge of the road is.

These approaches are fundamentally different because in the formersolution every road in the world would require the placement ofappropriate hardware as well as the maintenance of this hardware. Thisis obviously impractical. In the second case, the use of the globalpositioning satellite system (GPS), augmented by additional systems tobe described below, will provide the vehicle control system with anaccurate knowledge of its location. While it would be difficult toinstall and maintain hardware such as a wire down the center of the roadfor every road in the world, it is not difficult to survey every roadand record the location of the edges, and the lanes for that matter, ofeach road. This information must then be made available through one ormore of a variety of techniques to the vehicle control system.

Another case might be where a driver is proceeding down a road anddecides to change lines while another vehicle is in the driver's blindspot. Various companies are developing radar, ultrasonic or opticalsensors to warn the driver if the blind spot is occupied. The driver mayor may not heed this warning, perhaps due to an excessive false alarmrate, or he or she may have become incapacitated, or the system may failto detect a vehicle in the blind spot and thus the system will fail.

Consider an alternative technology where again each vehicle knowsprecisely where it is located on the earth surface and additionally cancommunicate this information to all other vehicles within a certainpotential danger zone relative to the vehicle. Now, when the driverbegins to change lanes, his or her vehicle control system knows thatthere is another vehicle in the blind spot and therefore will eitherwarn the driver or else prevent him or her from changing lanes therebyavoiding the accident.

Similarly, if a vehicle is approaching a stop sign, other traffic markeror red traffic light and the operator fails to bring the vehicle to astop, if the existence of this traffic light and its state (red in thisexample) or stop sign has been made available to the vehicle controlsystem, the system can warn the driver or seize control of the vehicleto stop the vehicle and prevent a potential accident. Additionally, ifan operator of the vehicle decides to proceed across an intersectionwithout seeing an oncoming vehicle, the control system will once againknow the existence and location and perhaps velocity of the oncomingvehicle and warn or prevent the operator from proceeding across theintersection.

Consider another example where water on the surface of a road isbeginning to freeze. Probably the best way that a vehicle control systemcan know that the road is about to become slippery, and therefore thatthe maximum vehicle speed must be significantly reduced, is to getinformation from some external source. This source can be sensorslocated on the highway that are capable of determining this conditionand transmitting it to the vehicle. Alternately, the probability oficing occurring can be determined analytically from meteorological dataand a historical knowledge of the roadway and communicated to thevehicle over a LEO or GEO satellite system, the Internet or an FMsub-carrier or other means. A combination of these systems can also beused.

Studies have shown that a combination of meteorological and historicdata can accurately predict that a particular place on the highway willbecome covered with ice. This information can be provided to properlyequipped vehicles so that the vehicle knows to anticipate slipperyroads. For those roads that are treated with salt to eliminate frozenareas, the meteorological and historical data will not be sufficient.Numerous systems are available today that permit properly equippedvehicles to measure the coefficient of friction between the vehicle'stires and the road. It is contemplated that perhaps police or otherpublic vehicles will be equipped with such a friction coefficientmeasuring apparatus and can serve as probes for those roadways that havebeen treated with salt. Information from these probe vehicles will befed into the information system that will then be made available tocontrol speed limits in those areas.

Countless other examples exist; however, from those provided above, itcan be seen that for the vehicle control system to function withouterror, certain types of information must be accurately provided. Theseinclude information permitting the vehicle to determine its absolutelocation and means for vehicles near each other to communicate thislocation information to each other. Additionally, map information thataccurately provides boundary and lane information of the road must beavailable. Also, critical weather or road-condition information isnecessary. The road location information need only be generated once andchanged whenever the road geometry is altered. This information can beprovided to the vehicle through a variety of techniques includingprerecorded media such as CD-ROM or DVD disks or through communicationsfrom transmitters located in proximity to the vehicle, satellites, radioand cellular phones.

Consider now the case of the congested highway. Many roads in the worldare congested and are located in areas where the cost of new roadconstruction is prohibitive or such construction is environmentallyunacceptable. It has been reported that an accident on such a highwaytypically ties up traffic for a period of approximately four times thetime period required to clear the accident. Thus, by eliminatingaccidents, a substantial improvement of the congested highway problem isobtained. This of course is insufficient. On such highways, each vehicletravels with a different spacing, frequently at different speeds and inthe wrong lanes. If the proper spacing of the vehicles could bemaintained, and if the risk of an accident could be substantiallyeliminated, vehicles under automatic control could travel atsubstantially higher velocities and in a more densely packedconfiguration thereby substantially improving the flow rate of vehicleson the highway by as much as a factor of 3 to 4 times. This not onlywill reduce congestion but also improve air pollution. Once again, ifeach vehicle knows exactly where it is located, can communicate itslocation to surrounding vehicles and knows precisely where the road islocated, then the control system in each vehicle has sufficientinformation to accomplish this goal.

Again, an intention of the system and process described here is tototally eliminate automobile accidents as well as reduce highwaycongestion. This process is to be designed to have no defectivedecisions. The process employs information from a variety of sources andutilizes that information to prevent accidents and to permit the maximumvehicle throughput on highways.

The information listed above is still insufficient. The geometry of aroad or highway can be determined once and for all, until erosion orconstruction alters the road. Properly equipped vehicles can know theirlocation and transmit that information to other properly equippedvehicles. There remains a variety of objects whose location is notfixed, which have no transmitters and which can cause accidents. Theseobjects include broken down vehicles, animals such as deer which wanderonto highways, pedestrians, bicycles, objects which fall off of trucks,and especially other vehicles which are not equipped with locationdetermining systems and transmitters for transmitting that informationto other vehicles. Part of this problem can be solved for congestedhighways by restricting access to these highways to vehicles that areproperly equipped. Also, these highways are typically in urban areas andaccess by animals can be effectively eliminated. Heavy fines can beimposed on vehicles that drop objects onto the highway. Finally, sinceevery vehicle and vehicle operator becomes part of the process, eachsuch vehicle and operator becomes a potential source of information tohelp prevent catastrophic results. Thus, each vehicle should also beequipped with a system of essentially stopping the process in anemergency. Such a system could be triggered by vehicle sensors detectinga problem or by the operator strongly applying the brakes, rapidlyturning the steering wheel or by activating a manual switch when theoperator observes a critical situation but is not himself in immediatedanger. An example of the latter case is where a driver witnesses a boxfalling off of a truck in an adjacent lane.

To solve the remaining problems, therefore, each vehicle should also beequipped with an anticipatory collision sensing system, or collisionforecasting system, which is capable of identifying or predicting andreacting to a pending accident. As the number of vehicles equipped withthe control system increases, the need for the collision forecastingsystem will diminish.

Once again, the operator will continue to control his vehicle providedhe or she remains within certain constraints. These constraints are likea corridor. As long as the operator maintains his vehicle within thisallowed corridor, he or she can operate that vehicle withoutinterference from the control system. That corridor may include theentire width of the highway when no other vehicles are present or it maybe restricted to all eastbound lanes, for example. In still other cases,that corridor may be restricted to a single line and additionally, theoperator may be required to keep his vehicle within a certain spacingtolerance from the preceding vehicle. If a vehicle operator wishes toexit a congested highway, he could operate his turn signal that wouldinform the control system of this desire and permit the vehicle tosafely exit from the highway. It can also inform other adjacent vehiclesof the operator's intent, which could then automatically cause thosevehicles to provide space for lane changing, for example. The highwaycontrol system is thus a network of individual vehicle control systemsrather than a single highway resident computer system.

Considering now the U.S. Department of Transportation (DOT) policy, inthe DOT FY 2000 Budget in Brief Secretary Rodney Slater states that“Historic levels of federal transportation investment . . . are proposedin the FY 2000 budget.” Later, Secretary Slater states that“Transportation safety is the number one priority.” DOT has estimatedthat $165 billion per year are lost in fatalities and injuries on U.S.roadways. Another $50 billion are lost in wasted time of people oncongested highways. Presented herein is a plan to eliminate fatalitiesand injuries and to substantially reduce congestion. The total cost ofimplementing this plan is minuscule compared to the numbers statedabove. This plan has been named the “Road to Zero Fatalities™”, or RtZF™for short.

The DOT Performance Plan FY 2000, Strategic Goal: Safety, states that“The FY 2000 budget process proposes over $3.4 billion for direct safetyprograms to meet this challenge.” The challenge is to “Promote thepublic health and safety by working toward the elimination of trafficrelated deaths, injuries and property damage”. The goal of the RtZF™, asdescribed below and which is a part of the present invention, is thesame and herein a plan is presented for accomplishing this goal. Theremainder of the DOT discussion centers around wishful thinking toreduce the number of transportation-related deaths, injuries, etc.However, the statistics presented show that in spite of this goal, thenumber of deaths is now increasing. As discussed below, this is theresult of a failed process.

Reading through the remainder of the DOT Performance Plan FY 2000, oneis impressed by the billions of dollars that are being spent to solvethe highway safety problem coupled with the enormous improvement thathas been made until the last few years. It can also be observed that theincrease in benefits from these expenditures has now disappeared. Forexample, the fatality rate per 100 million vehicle miles traveled fellfrom 5.5 to 1.7 in the period from the mid-1960s to 1994. But thisdecrease has now substantially stopped! This is an example of the law ofdiminishing returns and signals the need to take a totally new approachto solving this problem.

The U.S. Intelligent Vehicle Initiative (IVI) policy states thatsignificant funds have been spent on demonstrating various ITStechnologies. It is now time for implementation. With over 40,000fatalities and almost four million people being injured every year onU.S. roadways, it is certainly time to take affirmative action to stopthis slaughter. The time for studies and demonstrations is past.However, the deployment of technologies that are inconsistent with theeventual solution of the problem will only delay implementation of theproper systems and thereby result in more deaths and injuries.

A primary goal of the Intelligent Vehicle Initiative was to reducehighway related fatalities per 100 million vehicle miles traveled from1.7 in 1996 to 1.6 in 2000. Of course, the number of fatalities maystill increase due to increased road use. If this reduction infatalities comes about due to slower travel speeds, because of greatercongestion, then has anything really been accomplished? Similar commentsapply to the goal of reducing the rate of injury per 100 million vehiclemiles from 141 in 1996 to 128 in 2000. An alternate goal, as describedherein, is to have the technology implemented on all new vehicles by theyear 2010 that will eventually eliminate all fatalities and injuries. Asan intermediate milestone, it is proposed to have the technologyimplemented on all new vehicles by 2007 to reduce or eliminatefatalities caused by road departure, center (yellow) line crossing, stopsign infraction, rear end and excessive speed accidents. Inventionsdescribed herein will explain how these are goals can be attained.

In the IVI Investment Strategy, Critical Technology Elements AndActivities of the DOT, it says “The IVI will continue to expand theseefforts particularly in areas such as human factors, sensor performance,modeling and driver acceptance”. An alternate, more effective,concentration for investments would be to facilitate the deployment ofthose technologies that will reduce and eventually eliminate highwayfatalities. Driver acceptance and human factors will be discussed below.Too much time and resources have already been devoted to these areas.Modeling can be extremely valuable and sensor performance is in ageneral sense a key to eliminating fatalities.

On Jul. 15, 1998, the IVI light vehicle steering committee met andrecommended that the IVI program should be conducted as a governmentindustry partnership like the PNGV. This is believed to be quite wrongand it is believed that the IVI should now move vigorously toward thedeployment of proven technology.

The final recommendations of the committee was “In the next five years,the IVI program should be judged on addressing selected impedimentspreventing deployment, not on the effect of IVI services on accidentrates.” This is believed to be a mistake. The emphasis for the next fiveyears should be to deploy proven technologies and to start down the Roadto Zero Fatalities™. Five years from now technology should be deployedon production vehicles sold to the public that have a significant effecttoward reducing fatalities and injuries.

As described in the paper “Preview Based Control of A Tractor TrailerUsing DGPS For Preventing Road Departure Accidents” the basis of thetechnology proposed has been demonstrated.

DISCUSSION AND REVIEW OF RELEVANT ART

1. Vehicle Collision Warning and Control

The world is experiencing an unacceptable growth in traffic congestionand attention is increasingly turning to smart highway systems to solvethe problem. It has been estimated that approximately $240 billion willbe spent on smart highways over the next 20 years. All of theinitiatives currently being considered involve a combination ofvehicle-mounted sensors and sensors and other apparatus installed in oron the roadway. Such systems are expensive to install, difficult andexpensive to maintain and will thus only be used on major highways, ifat all. Although there will be some safety benefit from such systems, itwill be limited to the highways which have the system and perhaps toonly a limited number of lanes.

The RtZF™ system in accordance with the invention eliminates theshortcomings of the prior art by providing a system that does notrequire modifications to the highway. The information as to the locationof the highway is determined, as discussed above, by mapping the edgesof the roadway and the edges of the lanes of the roadway using a processwhereby the major roads of the entire country can be mapped at very lowcost. Thus, the system has the capability of reducing congestion as wellas saving lives on all major roads, not just those which have beenselected as high-speed guided lanes.

The ALVINN project of Carnegie Mellon University (Jochem, Todd M.,Pomerleau, Dean A., and Thorpe, Charles E., “Vision-Based Neural NetworkRoad and Intersection Detection and Traversal”, IEEE Conference onIntelligent Robots and Systems, Aug. 5–9, 1995, Pittsburgh, Pa., USA))describes an autonomous land vehicle using a neural network. The neuralnetwork is trained based on how a driver drives the vehicle given theoutput from a video camera. The output of the neural network is thedirection that the vehicle should travel in based on the inputinformation from the video camera and the training based on what a gooddriver would do. A similar system can be used in some embodiments of thepresent invention to guide a vehicle to a safe stop in the event thatthe driver becomes incapacitated or some other emergency situationoccurs wherein the driver is unable to control the vehicle. The input tothe neural network in this case would be the map information rather thana video camera. Additionally, a laser radar or terahertz radar imagingsystem of this invention could also be an input to the system. Thisneural network system can additionally take over in the event that anaccident becomes inevitable. Simple neural networks are probably notsufficient for this purpose and neural fuzzy, modular neural networks orcombination neural networks are probably required.

U.S. Pat. No. 5,479,173 to Yoshioka, et al. uses a steering anglesensor, a yaw rate sensor and a velocity of the vehicle sensor topredict the path that the vehicle will take. It uses a radar unit toidentify various obstacles that may be in the path of the vehicle, andit uses a CCD camera to try to determine that the road is changingdirection in front of the vehicle. No mention is made of the accuracywith which these determinations are made. It is unlikely that sub-meteraccuracy is achieved. If an obstacle is sensed, the brakes can beautomatically activated.

U.S. Pat. No. 5,540,298 to Yoshioka, et al. is primarily concerned withchanging the suspension and steering characteristics of the vehicle inorder to prevent unstable behavior of the vehicle in response to theneed to exercise a collision avoidance maneuver. The collisionanticipation system includes an ultrasonic unit and two optical laserradar units.

U.S. Pat. No. 5,572,428 to Ishida is concerned with using a radar systemplus a yaw rate sensor and a velocity sensor to determine whether avehicle will collide with another vehicle based on the area occupied byeach vehicle. Since radar cannot accurately determine this area, it hasto be assumed by the system.

U.S. Pat. No. 5,613,039 to Wang, et al. is a collision warning radarsystem utilizing a real time adaptive probabilistic neural network. Wangdiscusses that about 60% of roadway collisions could be avoided if theoperator of the vehicle was provided warning at least one-half secondprior to a collision. The radar system used by Wang uses two separatefrequencies. The reflective radar signals are analyzed by aprobabilistic neural network that provides an output signal indicativeof the likelihood and threat of a collision with a particular object. AFourier transform circuit converts the digitized reflective signal froma time series to a frequency representation. It is important to notethat in this case, as in the others above, true collision avoidance willnot occur since, without a knowledge of the roadway, two vehicles can beapproaching each other on a collision course, each following a curvedlane on a highway and yet the risk of collision is minimal due to thefact that each vehicle remains in its lane. Thus, true collisionavoidance cannot be obtained without an accurate knowledge of the roadgeometry.

U.S. Pat. No. 5,983,161 to Lemelson describes a GPS-based collisionavoidance and warning system that contains some of the features ofembodiments of the present invention. This patent is primarily concernedwith using centimeter-accuracy DGPS systems to permit vehicles on aroadway to learn and communicate their precise locations to othervehicles. In that manner, a pending collision can, in some cases, bepredicted.

Lemelson does not use an inertial navigation system for controlling thevehicle between GPS updates. Thus, the vehicle can travel a significantdistance before its position can be corrected. This can lead tosignificant errors. Lemelson also does not make use of accurate mapdatabase and thus it is unable to distinguish cases where two cars areon separate lanes but on an apparent collision course. Although variousradar and lidar systems are generally discussed, the concept of rangegating is not considered. Thus, the Lemelson system is unable to providethe accuracy and reliability required by the Road to Zero Fatalities™system described herein.

Since many of the concepts disclosed in the inventions herein make useof neural networks, a background of neural networks is important to thereader. The theory of neural networks including many examples can befound in several books on the subject including: (1) Techniques andApplication of Neural Networks, edited by Taylor, M. and Lisboa, P.,Ellis Horwood, West Sussex, England, 1993; (2) Naturally IntelligentSystems, by Caudill, M. and Butler, C., MIT Press, Cambridge Mass.,1990; (3) J. M. Zaruda, Introduction to Artificial Neural Systems, Westpublishing Co., N.Y., 1992, (4) Digital Neural Networks, by Kung, S. Y.,PTR Prentice Hall, Englewood Cliffs, N.J., 1993, Eberhart, R., Simpson,P., (5) Dobbins, R., Computational Intelligence PC Tools, AcademicPress, Inc., 1996, Orlando, Fla., (6) Cristianini, N. and Shawe-Taylor,J. An Introduction to Support Vector Machines and Other Kernel-BasedLearning Methods, Cambridge University Press, Cambridge England, 2000;(7) Proceedings of the 2000 6^(th) IEEE International Workshop onCellular Neural Networks and their Applications (CNNA 2000), IEEE,Piscataway N.J.; and (8) Sinha, N. K. and Gupta, M. M. Soft Computing &Intelligent Systems, Academic Press 2000 San Diego, Calif. The neuralnetwork pattern recognition technology is one of the most developed ofpattern recognition technologies. The invention described herein usescombinations of neural networks to improve the pattern recognitionprocess.

2. Accurate Navigation

U.S. Pat. No. 5,504,482 to Schreder describes an automobile equippedwith an inertial and satellite navigation system as well as a local areadigitized street map. The main use of this patent is for route guidancein the presence of traffic jams, etc. Schreder describes how informationas to the state of the traffic on a highway can be transmitted andutilized by a properly equipped vehicle to change the route the driverwould take in going to his destination. Schreder does not disclosesub-meter vehicle location accuracy determination, nevertheless, thispatent provides a good picture of the state of the art as can be seenfrom the following quoted paragraphs:

“ . . . there exists a wide range of technologies that havedisadvantageously not been applied in a comprehensive integrated mannerto significantly improve route guidance, reduce pollution, improvevehicular control and increase safety associated with the commonautomobile experience. For example, it is known that gyro based inertialnavigation systems have been used to generate three-dimensional positioninformation, including exceedingly accurate acceleration and velocityinformation over a relatively short travel distance, and that GPSsatellite positioning systems can provide three-dimensional vehicularpositioning and epoch timing, with the inertial system being activatedwhen satellite antenna reception is blocked during “drop out” forcontinuous precise positioning. It is also known that digitized terrainmaps can be electronically correlated to current vehicular transientpositions, as have been applied to military styled transports andweapons. For another example, it is also known that digitally encodedinformation is well suited to RF radio transmission within specifictransmission carrier bands, and that automobiles have been adapted toreceived AM radio, FM radio, and cellular telecommunication RFtransmissions. For yet another example, it is further known thatautomobile electronic processing has been adapted to automaticallycontrol braking, steering, suspension and engine operation, for example,anti-lock braking, four-wheel directional steering, dynamic suspensionstiffening during turns and at high speeds, engine governors limitingvehicular speed, and cruise control for maintaining a desired velocity.For still another example, traffic monitors, such as road embeddedmagnetic traffic light sensor loops and road surface traffic flow metershave been used to detect traffic flow conditions. While these sensors,meters, elements, systems and controls have served limited specificpurposes, the prior art has disadvantageously failed to integrate themin a comprehensive fashion to provide a complete dynamic route guidance,dynamic vehicular control, and safety improvement system.”

“Recently, certain experimental integrated vehicular dynamic guidancesystems have been proposed. Motorola has discussed an IntelligentVehicle Highway System in block diagram form in copyright dated 1993brochure. Delco Electronics has discussed another Intelligent VehicleHighway System also in block diagram form in Automotive News publishedon Apr. 12, 1993. These systems use compass technology for vehicularpositioning. However, displacement wheel sensors are plagued by tireslippage, tire wear and are relatively inaccurate requiringrecalibration of the current position. Compasses are inexpensive, butsuffer from drifting particularly when driving on a straight road forextended periods. Compasses can sense turns, and the system may then beautomatically recalibrated to the current position based upon sensing aturn and correlating that turn to the nearest turn on a digitized map,but such recalibration, is still prone to errors during excessivedrifts. Moreover, digitized map systems with the compass and wheelsensor positioning methods operate in two dimensions on a threedimensional road terrain injecting further errors between the digitizedmap position and the current vehicular position due to a failure tosense the distance traveled in the vertical dimension.”

“These Intelligent Vehicle Highway Systems appear to use GPS satellitereception to enhance vehicular tracking on digitized road maps as partof a guidance and control system. These systems use GPS to determinewhen drift errors become excessive and to indicate that recalibration isnecessary. However, the GPS reception is not used for automatic accuraterecalibration of current vehicular positioning, even though C-MIGITS andlike devices have been used for GPS positioning, inertial sensing andepoch time monitoring, which can provide accurate continuouspositioning.”

“These Intelligent Vehicle Highway Systems use the compass and wheelsensors for vehicular positioning for route guidance, but do not useaccurate GPS and inertial route navigation and guidance and do not useinertial measuring units for dynamic vehicular control. Even thoughdynamic electronic vehicular control, for example, anti-lock braking,anti-skid steering, and electronic control suspension have beencontemplated by others, these systems do not appear to functionallyintegrate these dynamic controls with an accurate inertial routeguidance system having an inertial measuring unit well suited fordynamic motion sensing. There exists a need to further integrate andimprove these guidance systems with dynamic vehicular control and withimproved navigation in a more comprehensive system.”

“These Intelligent Vehicle Highway Systems also use RF receivers toreceive dynamic road condition information for dynamic route guidance,and contemplate infrastructure traffic monitoring, for example, anetwork for road magnetic sensing loops, and contemplate the RFbroadcasting of dynamic traffic conditions for dynamic route guidance.The discussed two-way RF communication through the use of a transceiversuggests a dedicated two-way RF radio data system. While two-way RFcommunication is possible, the flow of necessary information between thevehicles and central system appears to be exceedingly lopsided. The flowof information from the vehicles to a central traffic radio data controlsystem may be far less than the required information from traffic radiodata control system to the vehicles. It seems that the amount ofbroadcasted dynamic traffic flow information to the vehicles would befar greater than the information transmitted from the vehicles to thecentral traffic control center. For example, road side incident oraccident emergency messages to a central system may occur far less thanthe occurrences of congested traffic points on a digitized map having alarge number of road coordinate points.”

“Conserving bandwidth capacity is an objective of RF communicationsystems. The utilization of existing infra structure telecommunicationswould seem cost-effective. AT&T has recently suggested improving theexisting cellular communication network with high-speed digital cellularcommunication capabilities. This would enable the use of cellulartelecommunications for the purpose of transmitting digital informationencoding the location of vehicular incidents and accidents. It thenappears that a vehicular radio data system would be cost-effectivelyused for unidirectional broadcasting of traffic congestion informationto the general traveling public, while using existing cellulartelecommunication systems for transmitting emergency information. Thecommunication system should be adapted for the expected volume ofinformation. The Intelligent Vehicular Highway Systems disadvantageouslysuggest a required two-way RF radio data system. The vast amount ofinformation that can be transmitted may tend to expand and completelyoccupy a dedicated frequency bandwidth. To the extent that any system isbi-directional in operation tends to disadvantageously requireadditional frequency bandwidth capacity and system complexity.”

2.1 GPS

Referring to FIG. 1, the presently implemented Global Positioning Systemwith its constellation of 24 satellites 2 is truly revolutionizingnavigation throughout the world. The satellites orbit the Earth in sixorbits 4. However, in order to reach its full potential for navigation,GPS needs to be augmented both to improve accuracy and to reduce thetime needed to inform a vehicle driver of a malfunction of a GPSsatellite, the so-called integrity problem.

The Global Positioning System (GPS) is a satellite-based navigation andtime transfer system developed by the U.S. Department of Defense. GPSserves marine, airborne and terrestrial users, both military andcivilian. Specifically, GPS includes the Standard Positioning Service(SPS) that provides civilian users with 100 meter accuracy as to thelocation or position of the user. It also serves military users with thePrecise Positioning Service that provides 20-meter accuracy for theuser. Both of these services are available worldwide with no requirementfor any local equipment.

2.2 DGPS, WAAS, LAAS and Pseudolites

Differential operation of GPS is used to improve the accuracy andintegrity of GPS. Differential GPS places one or more high quality GPSreceivers at known surveyed locations to monitor the received GPSsignals. This reference station(s) estimates the slowly varyingcomponents of the satellite range measurements, and forms a correctionfor each GPS satellite in view. The correction is broadcast to all DGPSusers within the coverage area of the broadcast facilities.

For a good discussion of DGPS, several are reproduced from OMNISTAR: inU.S. patent application Ser. No. 10/822,445, now U.S. Pat. No.7,085,637, and incorporated by reference herein.

The above description is provided to illustrate the accuracy which canbe obtained from the DGPS system. It is expected that the WAAS systemwhen fully implemented will provide the same benefits as provided by theOMNISTAR system. However, when the standard deviation of approximately0.5 meter is considered, it is evident that this WAAS system isinsufficient by itself and will have to be augmented by other systems toimprove the accuracy at least at this time.

GLONASS is a Russian system similar to GPS. This system providesaccuracy that is not as good as GPS.

The Projected Position Accuracy of GPS and GLONASS, Based on the CurrentPerformance is:

Horizontal Error (m) Vertical Error (m) (50%) (95%) (95%) GPS  7 18 34GLONASS 10 26 45

The system described here will achieve a higher accuracy than reportedin the above table due to the combination of the inertial guidancesystem that permits accurate changes in position to be determined andthrough multiple GPS readings. In other words, the calculated positionwill converge to the real position over time. The addition of DGPS willprovide an accuracy improvement of at least a factor of 10, which, withthe addition of a sufficient number of DGPS stations in some cases issufficient without the use of the carrier frequency correction. Afurther refinement where the vehicle becomes its own DGPS stationthrough the placement of infrastructure stations at appropriatelocations on roadways will further significantly enhance the systemaccuracy to the required level.

Multipath is the situation where more than one signal from a satellitecomes to a receiver with one of the signals resulting from a reflectionoff of a building or the ground, for example. Since multipath is afunction of geometry, the system can be designed to eliminate itseffects based on highway surveying and appropriate antenna design.Multipath from other vehicles can also be eliminated since the locationof the other vehicles will be known.

As discussed below, the Wide Area Augmentation System (WAAS) is beinginstalled by the US Government to provide DGPS for airplane landings.The intent is to cover the entire CONUS. This may be useful for much ofthe country for the purposes of this invention. Another alternativewould be to use the cellular phone towers, since there are so many ofthem, if they could be programmed to act as pseudolites.

An important feature of DGPS is that the errors from the GPS satelliteschange slowly with time and therefore, only the corrections need be sentto the user from time to time. Using reference receivers separated by25–120 km, accuracies from 2 cm to 1 m are achievable using local areaDGPS which is marginal for RtZF™. Alternately, through the placement ofappropriate infrastructure as described below even better accuracies areobtainable.

A type of wide area DGPS (WADGPS) system has been developed spans theentire U.S. continent which provides position RMS accuracy to betterthan about 50 cm. This system is described in the Bertiger, et al, “APrototype Real-Time Wide Area Differential GPS System,” Proceedings ofthe National Technical Meeting, Navigation and Positioning in theInformation Age, Institute of Navigation, Jan. 14–16, 1997 pp. 645–655.A RMS error of 50 cm would be marginally accurate for RtZF™. Many of theteachings of this invention, especially if the road edge and lanelocation error were much less, could be accomplished using more accuratesurveying equipment. The OmniSTAR system is another WADGPS system thatclaims 6 cm (1σ) accuracy.

A similar DGPS system which is now being implemented on a nationwidebasis is described in “DGPS Architecture Based on Separating ErrorComponents, Virtual Reference Stations and FM Subcarrier Broadcast”, byDifferential Corrections Inc., 10121 Miller Ave., Cupertino, Calif.95041. The system described in this paper promises an accuracy on theorder of about 10 cm.

Suggested DGPS update rates are usually less than twenty seconds. DGPSremoves common-mode errors, those errors common to both the referenceand remote receivers (not multipath or receiver noise). Errors are moreoften common when receivers are close together (less than 100 km).Differential position accuracies of 1–10 meters are possible with DGPSbased on C/A code SPS signals.

Using the CNET commercial system, 1 foot accuracies are possible if basestations are no more than 30 miles from the vehicle unit. This wouldrequire approximately 1000 base stations to cover CONUS. Alternately,the same accuracy is obtainable if the vehicle can become its own DGPSsystem every 30 miles as described herein.

Unfortunately, the respective error sources mentioned above rapidlydecorrelate as the distances between the reference station and thevehicle increases. Conventional DGPS is the terminology used when theseparation distances are sufficiently small that the errors cancel. Theterms single-reference and multi-reference DGPS are occasionally used inorder to emphasize whether there is a single reference station orwhether there are multiple ones. If it is desired to increase the areaof coverage and, at the same time, to minimize the number of fixedreference receivers, it becomes necessary to model the spatial andtemporal variations of the residual errors. Wide Area Differential GPS(WADGPS) is designed to accomplish this. Funds have now beenappropriated for the U.S. Government to deploy a national DGPS system.

The Wide Area Augmentation System (WAAS) is being deployed to replacethe Instrument Landing System used at airports across the country. TheWAAS system provides an accuracy of from about 1 to 2 meters for thepurpose of aircraft landing. If the vertical position of the vehicle isknown, as would be in the case of automobiles at a known position on aroad, this accuracy can be improved significantly. Thus, for many of thepurposes of this invention, the WAAS can be used to provide accuratepositioning information for vehicles on roadways. The accuracy of theWAAS is also enhanced by the fact that there is an atomic clock in everyWAAS receiver station that would be available to provide great accuracyusing carrier phase data. With this system, sub-meter accuracies arepossible for some locations.

The WAAS is based on a network of approximately 35 ground referencestations. Signals from GPS satellites are received by aircraft receiversas well as by ground reference stations. Each of these referencestations is precisely surveyed, enabling each to determine any error inthe GPS signals being received at its own location. This information isthen passed to a wide area master station. The master station calculatescorrection algorithms and assesses the integrity of the system. Thisdata is then put into a message format and sent to a ground earthstation for uplink to a geostationary communications satellite. Thecorrective information is forwarded to the receiver on board theaircraft, which makes the needed adjustments. The communicationssatellites also act as additional navigation satellites for theaircraft, thus, providing additional navigation signals for positiondetermination.

This system will not meet all of FAA's requirements. For category IIIlandings, the requirement is 1.6-m vertical and horizontal accuracy. Toachieve this, FAA is planning to implement a network of local areadifferential GPS stations that will provide the information to aircraft.This system is referred to as the Local Area Augmentation System (LAAS).

The WAAS system, which consists of a network of earth stations andgeo-synchronous satellites, is currently being funded by the U.S.Government for aircraft landing purposes. Since the number of peoplethat die yearly in automobile accidents greatly exceeds those killed inairplane accidents, there is clearly a greater need for a WAAS-typesystem for solving the automobile safety problem using the teachings ofthis invention. Also, the reduction in required highway fundingresulting from the full implementation of this invention would more thanpay for the extension and tailoring of the WAAS to cover the nation'shighways.

The Local Area Augmented System (LAAS) is also being deployed inaddition to the WAAS system to provide even greater coverage for theareas surrounding major airports. According to Newsletter of theInstitute of Navigation, 1997, “the FAA's schedule for (LAAS) forCategory II and III precision instrument approaches calls fordevelopment of standards by 1998 that will be sufficient to complete aprototype system by 2001. The next step will be to work out standardsfor an operational system to be fielded in about 2005, that could servenationwide up to about 200 runways for Cat II–III approaches.”

In a country like the United States, which has many airfields, a WAAScan serve a large market and is perhaps most effective for the controlof airplane landings. The best way for other countries, with fewerairports, to participate in the emerging field of GPS-based aviationaids may be to build LAAS. In countries with a limited number ofairports, LAAS is not very expensive while the costs of building a WAASto get Category I type accuracy is very expensive. However, with theadded benefit of less highway construction and greater automobilesafety, the added costs for a WAAS system may well be justified for muchof the world.

For the purposes of the RtZF™ system, both the WAAS and LAAS would beuseful but probably insufficient unless the information is used in adifferent mathematical system such as used by the OmniSTAR™ WADGPSsystem. Unlike an airplane, there are many places where it might not bepossible to receive LAAS and WAAS information or, even more importantly,the GPS signals themselves with sufficient accuracy and reliability.Initial RtZF™ systems may therefore rely on the WAAS and LAAS but as thesystem develops more toward the goal of zero fatalities, road-basedsystems which permit a vehicle to pinpoint its location will bepreferred. However, there is considerable development ongoing in thisfield so that all systems are still candidates for use with RtZF™ systemand the most cost effective will be determined in time.

Pseudolites are artificial satellite like structures, located on theearth surface, that can be deployed to enhance the accuracy of the DGPSsystem. Such structures could become part of the RtZF™ system.

2.3 Carrier Phase Measurements

An extremely accurate form of GPS is Carrier Based Differential GPS.This form of GPS utilizes the 1.575 GHz carrier component of the GPSsignal on which the Pseudo Random Number (PRN) code and the datacomponent are superimposed. Current versions of Carrier BasedDifferential GPS involve generating position determinations based on themeasured phase differences at two different antennas, a base station orpseudolite and the vehicle, for the carrier component of a GPS signal.This technique initially requires determining how many integerwave-lengths of the carrier component exist between the two antennas ata particular point in time. This is called integer ambiguity resolution.A number of approaches currently exist for integer ambiguity resolution.Some examples can be found in U.S. Pat. No. 5,583,513 and U.S. Pat. No.5,619,212. Such systems can achieve sub-meter accuracies and, in somecases, accuracies of about 1 cm or less. U.S. Pat. No. 5,477,458discusses a DGPS system that is accurate to about 5 cm with the basestations located on a radius of about 3000 km. With such a system, veryfew base stations would be required to cover the CONUS. This systemstill suffers from the availability of accurate signals at the vehicleregardless of its location on the roadway and the location ofsurrounding vehicles and objects. Nevertheless, the principle of usingthe carrier frequency to precisely determine the location of a vehiclecan be used with the highway-based systems described below to provideextreme location accuracies.

Several attempts to improve the position accuracy of GPS are discussedhere, for example, the Wide Area Augmentation System (WAAS), the LocalArea Augmentation System (LAAS) and various systems that make use of thecarrier phase.

A paper by S. Malys et al., titled “The GPS Accuracy ImprovementInitiative” provides a good discussion of the errors inherent in the GPSsystem without using differential corrections. It is there reported thatthe standard GPS provides a 9-meter RMS 3-D navigational accuracy toauthorize precise positioning service users. This reference indicatesthat there are improvements planned in the GPS system that will furtherenhance its accuracy. The accuracies of these satellites independentlyof the accuracies of receiving units is expected to be between 1 and 1.5meters RMS. Over the past eight years of GPS operations, a 50% (4.6meter to 2.3 meter) performance improvement has been observed for thesignal in space range errors. This, of course, is the RMS error. Theenhancements contained in the accuracy improvement initiative willprovide another incremental improvement from the current 2.3 meters to1.3 meters and perhaps to as low as 40 centimeters.

Pullen, Samuel, Enge, Per and Parkinson, Bradford, “Simulation-BasedEvaluation of WAAS Performance: Risk and Integrity Factors” discussesthe accuracy that can be expected from the WAAS system. This paperindicates that the standard deviation for WAAS is approximately 1 meter.To get more accurate results requires more closely spaced differentialstations. Using DGPS stations within 1,500 kilometers from the vehicle,high accuracy receivers can determine a location within 3 metersaccuracy for DGPS according to the paper. Other providers of DGPScorrections claim considerably better accuracies.

From a paper by J. F. Zumberge, M. M. Watkins and F. H. Webb, titled“Characteristics and Applications of Precise GPS Clock Solutions Every30 Seconds”, Journal of the Institute of Navigation, Vol. 44, No. 4,Winter 1997–1998, it appears that by using the techniques described inthis reference, the WAAS system could eventually be improved to provideaccuracies in the sub-decimeter range for moving vehicles without theneed for other DGPS systems. This data would be provided every 30seconds.

W. I. Bertiger et al., “A Real-Time Wide Area Differential GPS System”,Journal of the Institute of Navigation, Vol. 44, No. 4, Winter1997–1998. This paper describes the software that is to be used with theWAAS System. The WAAS System is to be completed by 2001. The goal of theresearch described in this paper is to achieve sub-decimeter accuraciesworldwide, effectively equaling local area DGPS performance worldwide.The full computation done on a Windows NT computer adds only about 3milliseconds. The positioning accuracy is approximately 25 centimetersin the horizontal direction. That is, the RMS value so that gives anerror at +3 sigma of 1.5 meters. Thus, this real time wide areadifferential GPS system is not sufficiently accurate for the purposes ofsome embodiments of this invention. Other systems claim higheraccuracies.

According to the paper by R. Braff, titled “Description of the FAA'sLocal Area Augmentation System (LAAS)”, Journal of the Institute ofNavigation, Vol. 44, No. 4, Winter 1997–1998, the LAAS System is theFAA's ground-based augmentation system for local area differential GPS.It is based on providing corrections of errors that are common to bothground-based and aircraft receivers. These corrections are transmittedto the user receivers via very high frequency (VHF), line of sight radiobroadcast. LAAS has the capability of providing accuracy on the order of1 meter or better on the final approach segment and through rollout.LAAS broadcasts navigational information in a localized service volumewithin approximately 30 nautical miles of the LAAS ground segment.

O'Connor, Michael, Bell, Thomas, Elkaim, Gabriel and Parkinson,Bradford, “Automatic Steering of Farm Vehicles Using GPS” describes anautomatic steering system for farm vehicles where the vehicle lateralposition error never deviated by more than 10 centimeters, using acarrier phase differential GPS system whereby the differential stationwas nearby.

The following quote is from Y. M. Al-Haifi et al., “PerformanceEvaluation of GPS Single-Epoch On-the Fly Ambiguity Resolution”, Journalof the Institute of Navigation, Vol. 44, No. 4, Winter 1997–1998. Thistechnique demonstrates sub-centimeter precision results all of the timeprovided that at least five satellites are available and multipatherrors are small. A resolution of 0.001 cycles is not at all unusual forgeodetic GPS receivers. This leads to a resolution on the order of 0.2millimeters. In practice, multipath affects, usually from nearbysurfaces, limit the accuracy achievable to around 5 millimeters. It iscurrently the case that the reference receiver can be located within afew kilometers of the mobile receiver. In this case, most of the otherGPS error sources are common. The only major problem, which needs to besolved to carry out high precision kinematic GPS, is the integerambiguity problem. This is because at any given instant, the wholenumber of cycles between the satellite and the receiver is unknown. Therecovery of the unknown whole wavelengths or integer ambiguities istherefore of great importance to precise phase positioning. Recently, alarge amount of research has focused on so-called “on the fly” (OTF)ambiguity resolution methodologies in which the integer ambiguities aresolved for while the unknown receiver is in motion.

The half-second processing time required for this paper represents 44feet of motion for a vehicle traveling at 60 mph, which would beintolerable unless supplemented by an inertial navigation system. Thebasic guidance system in this case would have to be the laser or MEMSgyro on the vehicle. With a faster PC, one-tenth a second processingtime would be achievable, corresponding to approximately 10 feet ofmotion of the vehicle, putting less reliance on the laser gyroscope.Nowhere in this paper is the use of this system on automobilessuggested. The technique presented in this paper is a single epoch basis(OTF) ambiguity resolution procedure that is insensitive to cycle slips.This system requires the use of five or more satellites which suggeststhat additional GPS satellites may need to be launched to make the smarthighway system more accurate.

F. van Diggelen, “GPS and GPS+GLONASS RTK”, ION-GPS, September 1997 “NewProducts Descriptions”, gives a good background of real time kinematicsystems using the carrier frequency. The products described in thispaper illustrate the availability of centimeter level accuracies for thepurposes of the RtZF™ system. The product described in F. van Diggelenrequires a base station that is no further than 20 kilometers away.

A paper by J. Wu and S. G. Lin, titled “Kinematic Positioning with GPSCarrier Phases by Two Types of Wide Laning”, Journal of the Institute ofNavigation, Vol. 44, No. 4, Winter 1997 discusses that the solution ofthe integer ambiguity problem can be simplified by performing otherconstructs other than the difference between the two phases. One exampleis to use three times one phase angle, subtracted from four timesanother phase angle. This gives a wavelength of 162.8 centimeters vs.86.2 for the single difference. Preliminary results with a 20-kilometerbase line show a success rate as high as 95% for centimeter levelaccuracies.

A paper by R. C. Hayward et al., titled “Inertially Aided GPS BasedAttitude Heading Reference System (AHRS) for General Aviation Aircraft”provides the list of inertial sensors that can be used with theteachings of embodiments of this invention.

K. Ghassemi et al., “Performance Projections of GPS IIF”, describes theperformance objectives for a new class of GPS 2F satellites scheduled tobe launched in late 2001.

Significant additional improvement can be obtained for the WAAS systemusing the techniques described in the paper “Incorporation of orbitaldynamics to improve wide-area differential GPS” by J. Ceva, W.Bertinger, R. Mullerschoen, T. Yunck and B. Parkinson, Institute onNavigation, Meeting on GPS Technology, Palm Springs, Calif., September1995.

Singh, Daljit and Grewal, Harkirat, “Autonomous Vehicle using WADGPS”,discusses ground vehicle automation using wide-area DGPS. Though thisreference describes many of the features of embodiments of the presentinvention, it does not disclose sub-meter accuracy or sub-meter accuratemapping.

U.S. Pat. No. 5,272,483 to Kato describes an automobile navigationsystem. This system attempts to correct for the inaccuracies in the GPSsystem through the use of an inertial guidance, geomagnetic sensor, orvehicle crank shaft speed sensor. However, it is unclear as to whetherthe second position system is actually more accurate than the GPSsystem. This combined system, however, cannot be used for sub-meterpositioning of an automobile.

U.S. Pat. No. 5,383,127 to Shibata uses map matching algorithms tocorrect for errors in the GPS navigational system to provide a moreaccurate indication of where the vehicle is or, in particular, on whatroad the vehicle is. This procedure does not give sub-meter accuracy.Its main purpose is for navigation and, in particular, in determiningthe road on which the vehicle is traveling.

U.S. Pat. No. 5,416,712 to Geier, et al. relates generally to navigationsystems and more specifically to global positioning systems that usedead reckoning apparatus to fill in as backup during periods of GPSshadowing such as occur amongst obstacles, e.g., tall buildings in largecities. This patent shows a method of optimally combining theinformation available from GPS even when less than 3 or 4 satellites areavailable with information from a low-cost, inertial gyro, having errorsthat range from 1–5%. This patent provides an excellent analysis of howto use a modified Kalman filter to optimally use the availableinformation.

U.S. Pat. No. 5,606,506 to Kyrtsos provides a good background of the GPSsatellite system. It describes a method for improving the accuracy ofthe GPS system using an inertial guidance system. This is based on thefact that the GPS signals used by Kyrtsos do not contain a differentialcorrection and the selective access feature is on. Key paragraphs fromthis application that describe subject matter applicable to embodimentsof the instant invention follow.

“Several national governments, including the United States (U.S.) ofAmerica, are presently developing a terrestrial position determinationsystem, referred to generically as a global positioning system (GPS). AGPS is a satellite-based radio-navigation system that is intended toprovide highly accurate three-dimensional position information toreceivers at or near the surface of the Earth.

“The U.S. government has designated its GPS the “NAVSTAR.” The NAVSTARGPS is expected to be declared fully operational by the U.S. governmentin 1993. The government of the former Union of Soviet SocialistRepublics (USSR) is engaged in the development of a GPS known as“GLONASS”. Further, two European systems known as “NAVSAT” and “GRANAS”are also under development.” For ease of discussion, the followingdisclosure focuses specifically on the NAVSTAR GPS. The invention,however, has equal applicability to other global positioning systems.

“In the NAVSTAR GPS, it is envisioned that four orbiting GPS satelliteswill exist in each of six separate circular orbits to yield a total oftwenty-four GPS satellites. Of these, twenty-one will be operational andthree will serve as spares. The satellite orbits will be neither polarnor equatorial but will lie in mutually orthogonal inclined planes.”

“Each GPS satellite will orbit the Earth approximately once every 12hours. This coupled with the fact that the Earth rotates on its axisonce every twenty-four hours causes each satellite to complete exactlytwo orbits while the Earth turns one revolution.”

“The position of each satellite at any given time will be preciselyknown and will be continuously transmitted to the Earth. This positioninformation, which indicates the position of the satellite in space withrespect to time (GPS time), is known as ephemeris data.”

“In addition to the ephemeris data, the navigation signal transmitted byeach satellite includes a precise time at which the signal wastransmitted. The distance or range from a receiver to each satellite maybe determined using this time of transmission which is included in eachnavigation signal. By noting the time at which the signal was receivedat the receiver, a propagation time delay can be calculated. This timedelay when multiplied by the speed of propagation of the signal willyield a “pseudorange” from the transmitting satellite to the receiver.”

“The range is called a “pseudorange” because the receiver clock may notbe precisely synchronized to GPS time and because propagation throughthe atmosphere introduces delays into the navigation signal propagationtimes. These result, respectively, in a clock bias (error) and anatmospheric bias (error). Clock biases may be as large as severalmilliseconds.”

“Using these two pieces of information (the ephemeris data and thepseudorange) from at least three satellites, the position of a receiverwith respect to the center of the Earth can be determined using passivetriangulation techniques.”

“Triangulation involves three steps. First, the position of at leastthree satellites in “view” of the receiver must be determined. Second,the distance from the receiver to each satellite must be determined.Finally, the information from the first two steps is used togeometrically determine the position of the receiver with respect to thecenter of the Earth.”

“Triangulation, using at least three of the orbiting GPS satellites,allows the absolute terrestrial position (longitude, latitude, andaltitude with respect to the Earth's center) of any Earth receiver to becomputed via simple geometric theory. The accuracy of the positionestimate depends in part on the number of orbiting GPS satellites thatare sampled. Using more GPS satellites in the computation can increasethe accuracy of the terrestrial position estimate.”

“Conventionally, four GPS satellites are sampled to determine eachterrestrial position estimate. Three of the satellites are used fortriangulation, and a fourth is added to correct for the clock biasdescribed above. If the receiver's clock were precisely synchronizedwith that of the GPS satellites, then this fourth satellite would not benecessary. However, precise (e.g., atomic) clocks are expensive and are,therefore, not suitable for all applications.”

For a more detailed discussion on the NAVSTAR GPS, see Parkinson,Bradford W. and Gilbert, Stephen W., “NAVSTAR: Global PositioningSystem—Ten Years Later, Proceedings of the IEEE, Vol. 71, No. 10,October 1983; and GPS: A Guide to the Next Utility,” published byTrimble Navigation Ltd., Sunnyvale, Calif., 1989, pp. 147. For adetailed discussion of a vehicle positioning/navigation system whichuses the NAVSTAR GPS, see commonly owned U.S. patent application Ser.No. 7/628,560, entitled “Vehicle Position Determination System andMethod,” filed Dec. 3, 1990.”

“The NAVSTAR GPS envisions two modes of modulation for the carrier waveusing pseudorandom signals. In the first mode, the carrier is modulatedby a “C/A signal” and is referred to as the “Coarse/Acquisition mode”.The Coarse/Acquisition or C/A mode is also known as the “StandardPositioning Service”. The second mode of modulation in the NAVSTAR GPSis commonly referred to as the “precise” or “protected” (P) mode. TheP-mode is also known as the “Precise Positioning Service”.

The P-mode is intended for use only by Earth receivers specificallyauthorized by the U.S. government. Therefore, the P-mode sequences areheld in secrecy and are not made publicly available. This forces mostGPS users to rely solely on the data provided via the C/A mode ofmodulation (which results in a less accurate positioning system) “Inaddition to the clock error and atmospheric error, other errors whichaffect GPS position computations include receiver noise, signalreflections, shading, and satellite path shifting (e.g., satellitewobble). These errors result in computation of incorrect pseudorangesand incorrect satellite positions. Incorrect pseudoranges and incorrectsatellite positions, in turn, lead to a reduction in the precision ofthe position estimates computed by a vehicle positioning system.”

U.S. Pat. No. 5,757,646 to Talbot, et al. illustrates the manner inwhich centimeter level accuracy on the fly in real time is obtained. Itis accomplished by double differencing the code and carrier measurementsfrom a pair of fixed and roving GPS receivers. This patent also presentsan excellent discussion of the problem and various prior solutions as inthe following paragraphs:

“When originally conceived, the global positioning system (GPS) that wasmade operational by the United States Government was not foreseen asbeing able to provide centimeter-level position accuracies. Suchaccuracies are now commonplace.”

“Extremely accurate GPS receivers depend on phase measurements of theradio carriers that they receive from various orbiting GPS satellites.Less accurate GPS receivers simply develop the pseudoranges to eachvisible satellite based on the time codes being sent. Within thegranularity of a single time code, the carrier phase can be measured andused to compute range distance as a multiple of the fundamental carrierwavelength. GPS signal transmissions are on two synchronous, butseparate carrier frequencies “L1” and “L2”, with wavelengths of nineteenand twenty-four centimeters, respectively. Thus, within nineteen ortwenty-four centimeters, the phase of the GPS carrier signal will change360°.”

“However the numbers of whole cycle (360°) carrier phase shifts betweena particular GPS satellite and the GPS receiver must be resolved. At thereceiver, every cycle will appear the same. Therefore there is an“integer ambiguity”. The computational resolution of the integerambiguity has traditionally been an intensive arithmetic problem for thecomputers used to implement GPS receivers. The traditional approaches tosuch integer ambiguity resolution have prevented on-the-fly solutionmeasurement updates for moving GPS receivers with centimeter accurateoutputs. Very often such highly accurate GPS receivers have requiredlong periods of motionlessness to produce a first and subsequentposition fix.”

“There are numerous prior art methods for resolving integer ambiguities.These include integer searches, multiple antennas, multiple GPSobservables, motion-based approaches, and external aiding. Searchtechniques often require significant computation time and are vulnerableto erroneous solutions when only a few satellites are visible. Moreantennas can improve reliability considerably. If carried to an extreme,a phased array of antennas results whereby the integers are completelyunambiguous and searching is unnecessary. But for economy the minimumnumber of antennas required to quickly and unambiguously resolve theintegers, even in the presence of noise, is preferred.”

“One method for integer resolution is to make use of the otherobservables that modulate a GPS timer. The pseudo-random code can beused as a coarse indicator of differential range, although it is verysusceptible to multipath problems. Differentiating the L1 and L2carriers provides a longer effective wavelength, and reduces the searchspace. However dual frequency receivers are expensive because they aremore complicated. Motion-based integer resolution methods make use ofadditional information provided by platform or satellite motion. Butsuch motion may not always be present when it is needed.”

This system is used in an industrial environment where the four antennasare relatively close to each other. Practicing teachings of thisinvention permits a navigational computer to solve for the position ofthe rover vehicle to within a few centimeters on the fly ten times asecond. An example is given where the rover is an airplane.

The above comments related to the use of multiple antennas to eliminatethe integer ambiguity suggest that if a number of vehicles are nearbyand their relative positions are known, the ambiguity can be resolved inthis manner.

2.4 Inertial Navigation System

An example of how various sensors other than the GPS and PPS systemsdescribed in this invention can be found in “Magnetometer andDifferential Carrier-Phase GPS-Aided INS for Advanced Vehicle Control”,IEEE Transactions on Robotics and Automation, Vol. 19, No. 2, April2003.

3. Maps and Mapping

It is intended that the map database of embodiments of the instantinvention will conform to the open GIS specification. This will permitsuch devices to additionally obtain on-line consumer informationservices such as driving advisories, digital yellow pages that givedirections, local weather pictures and forecasts and video displays oflocal terrain since such information will also be in the GIS databaseformat.

A paper by O'Shea, Michael and Shuman, Valerie entitled “Looking Ahead:Map Databases in Predictive Positioning and Safety Systems” discussesmap databases which can assist radar and image-processing systems ofthis invention since the equipped vehicle would know where the roadahead is and can therefore distinguish the lane of the precedingvehicle. No mention, however, is made in this reference of how this isaccomplished through range gating or other means. This reference alsomentions that within five years it may be possible to provide real timevehicle location information of one-meter accuracy. However, it mentionsthat this will be limited to controlled access roads such as interstatehighways. In other words, the general use of this information on allkinds of roads for safety purposes is not contemplated. This referencealso states that “road geometry, for example, may have to be accurate towithin one meter or less as compared to the best available accuracy of15 meters today”. This reference also mentions the information aboutlane configuration that can be part of the database including the widthof each lane, the number of lanes, etc., and that this can be used todetermine driver drowsiness. This reference also states that “at normalvehicle speeds, the vehicle location must be updated every fewmilliseconds”. It is also stated that the combination of radar and mapdata can help to interpret radar information such as the situation wherea radar system describes an overpass as a semi truck. Image processingin this reference is limited to assessing road conditions such as rain,snow, etc. The use of a laser radar system, for example, is notcontemplated by this reference. The use of this information for roaddepartures warnings is also mentioned, as is lane following. Thereference also mentions that feedback from vehicles can be used toimprove map configurations.

A great flow of commercially available data will begin with the newgeneration of high resolution (as fine as about 1 meter) commercialearth imaging satellites from companies like EarthWatch and SPOT Image.Sophisticated imaging software is being put in place to automaticallyprocess these imaging streams into useful data products. This data canbe used to check for gross errors in the map database.

According to Al Gore, in “The Digital Earth: Understanding our Planet inthe 21^(st) Century”, California Science Center, Jan. 31, 1998, theClinton Administration licensed commercial satellites to provide onemeter resolution imaging beginning in 1998. Such imaging can be combinedwith digital highway maps to provide an accuracy and reality check.

U.S. Pat. No. 5,367,463 to Tsuji describes a vehicle azimuth determiningsystem. It uses regression lines to find the vehicle on a map when thereare errors in the GPS and map data. This patent does not give sub-meteraccuracy. The advantage of this invention is that it shows a method ofcombining both map matching data and GPS along with a gyroscope andvehicle velocity and odometer data to improve the overall locationaccuracy of the vehicle.

4. Precise Positioning

For the purposes herein, a Precise Positioning Station, or PPS, willmean any system that involves the existence of or placement of adetectable infrastructure on or near a roadway that when used inconjunction with an accurate map permits a vehicle to determine itsprecise location. In other words, PPS can be any system that canrecognize anything in or on the infrastructure and thereby, inconjunction with an accurate map, can locate the vehicle. Suchdetectable infrastructure can comprise a MIR triad, radar reflectors,SAW devices, RFID devices, devices or marks detectable visibly such asbar codes or other recognizable objects including edges of buildings,poles, signs or the like, magnetic markers or any other object whoseposition is precisely known and/or is detectable in a manner thatpermits the vehicle to determine its position relative to the device orabsolutely and where the object is noted on a map database residingwithin the vehicle. An alternative procedure is to map the reflectivesignature of the road environment and, using a laser, radar, terahertzor similar system, a vehicle can compare the sensed reflective signaturewith that recorded and thereby determine its location. As theenvironment changes with the seasons, there will be segments of thesignature that are unreliable but since a reasonable adjustment distancemight be once per mile it is quite likely that somewhere during a mileof travel that the reflective signature will be invariant over time.Bridge abutments, roadside signs or light poles, for example, would nottypically change from one time of the year to another and thus could beused as quite accurate markers of position along the road. Such a systemhas the advantage that no additions to the infrastructure would berequired. When PPS or Precise Positioning Station is referred to below,it is generally intended to include all of these devices and/or methods.

If two vehicles are traveling near each other and have establishedcommunications, and assuming that each vehicle can observe at least fourof the same GPS satellites, each vehicle can send the satelliteidentification and the time of arrival of the signal at a particularepoch to the other. Then, each vehicle can determine the relativeposition of the other vehicle as well as the relative clock error. Asone vehicle passes a Precise Positioning Station (PPS), it knows exactlywhere it is and thus the second vehicle also knows exactly where it isand can correct for satellite errors. All vehicles that are incommunication with the vehicle at the PPS similarly can determine theirexact position and the system approaches perfection. This concept isbased on the fact that the errors in the satellite signals are identicalfor all vehicles that are within a mile or so of each other.Furthermore, each vehicle can set its onboard clock since the vehiclepassing the PPS can do so, and communicate the exact time to the others,and then each vehicle can know the carrier phase of each satellitesignal at the PPS and thus invoke carrier phase DGPS.

When the operator begins operating his vehicle with a version of theRtZF™ system of this invention, he or she will probably not be near areference point as determined by one of the radar reflector, MIR or RFIDor other landmark locator systems as discussed below as part of thisinvention, for example. In this situation, he or she will use thestandard GPS system with the WAAS or other DGPS corrections such asavailable from OmniStar™, the U.S. Government or other provider. Thiswill provide accuracy of between a few meters to 6 centimeters. Thisaccuracy might be further improved as he or she travels down the roadthrough map-matching or through communication with other vehicles. Thevehicle will know, however, that is not operating in the high accuracymode. As soon as the vehicle (vehicle #1) passes a radar reflector, SAW,MIR, RFID or equivalent precise positioning system, it will be able tocalculate exactly where it is within a few centimeters and the vehiclewill know that it is in the accurate mode. Similarly, when anothervehicle passes through a precise positioning station and learns itsprecise location it can communicate this fact with other vehicles in itsvicinity (5 miles, for example) along with the latest GPS satellitetransmissions. Each other vehicle will then be able to calculate itsrelative location extremely accurately and thus know its position almostas accurately as the vehicle that just passed through the precisepositioning station. Furthermore, if vehicle #1 also has an accurateclock, as further described below, it can record the phase of eachcarrier wave from each satellite and predict that phase for perhaps anhour into the future. This then permits vehicle #1 to switch to carrierphase DGPS and know its precise position relative to the precisepositioning station, and thus on the earth, until the clock accuracydegrades its knowledge of the carrier phase at the precise positioningstation. Through continuous communication between vehicle #1 and othervehicles, all vehicles in the vicinity can similarly operate in thecarrier phase DGPS mode without the need for the installation andmaintenance of local DGPS stations. Thus, the addition of a few precisepositioning stations at very low cost permits each vehicle traveling onthe road to know its precise location on the earth and for the system toapproach perfection, a necessary requirement for achieving zerofatalities. For high-speed travel on a controlled highway, frequentprecise positioning stations can be inexpensively provided and eachvehicle can thereby be accurately contained within its proper corridor.Also, the size of the corridors that the vehicle is permitted to travelin can be a function of the accuracy state of the vehicle.

A paper by Han, Shaowei entitled “Ambiguity Recovery For Long-Range GPSKinematic Positioning” appears to say that if a mobile receiver isinitially synchronized with a fixed receiver such that there is nointeger ambiguity, and if the mobile receiver then travels away from thefixed receiver, and during the process it loses contact with thesatellites for a period of up to five minutes, that the carrier phasecan be recovered and the ambiguity eliminated, providing againcentimeter-range accuracies. Presumably, the fixed station is providingthe differential corrections. This is important for embodiments of theinstant invention since the integer ambiguity can be eliminated eachtime the vehicle passes a Precise Positioning Station (PPS) as explainedbelow. After that, a five-minute loss of GPS signals should never occur.Thus, carrier phase accuracies will eventually be available to allvehicles. Note that the integer ambiguity problem disappears when theGPS satellites provide more frequencies. If, for example, each satellitewould broadcast two frequencies with each frequency being a prime numberof cycles per second, there would be no integer ambiguity problem. Dueto the problem of identifying large prime numbers, other schemes can beused such that the relative phase of one carrier to the other does notrepeat in the space from the vehicle to the satellite or if it doesrepeat, it repeats only a few times. This problem becomes simpler asmore frequencies are added as for three frequencies, for example, thephase relation between any two can repeat as long as the phaserelationships between all three don't repeat very often. Also, withmultiple frequencies the DGPS corrections become less important and insome cases may not be needed. This is because each frequency isdiffracted a different amount by the ionosphere and therefore thediffraction or cash frequency can be determined. A new civilianfrequency is scheduled to be introduced by the U.S. Government as partof the NAVSTAR system and the forthcoming European GALILEO system isplanned to have multiple frequencies for civilian use.

U.S. Pat. No. 5,361,070 to McEwan, although describing a motiondetector, discusses technology which is used as part of a system topermit a vehicle to precisely know where it is on the face of the earthat particular locations. The ultra wideband 200 picosecond radar pulseemitted by the low power radar device of McEwan is inherently a spreadspectrum pulse which generally spans hundreds of megahertz to severalgigahertz. A frequency allocation by the FCC is not relevant.Furthermore, many of these devices may be co-located withoutinterference. The concept of this device is actually discussed invarious forms in the following related patents to McEwan. The followingcomments will apply to these patents as a group.

U.S. Pat. No. 5,510,802 to McEwan describes a time of flightradio-location system similar to what is described below. In this case,however, a single transmitter sends out a pulse, which is received bythree receivers to provide sub-millimeter resolution. The range of thisdevice is less than about 10 feet.

The concept described in McEwan's U.S. Pat. No. 5,519,400 is that theMIR signal can be modulated with a coded sequence to permit positiveidentification of the sending device. In an additional McEwan patent,U.S. Pat. No. 5,589,838, a short-range radio-location system isdescribed. Additionally, in U.S. Pat. No. 5,774,091, McEwan claims thatthe MIR system will operate to about 20 feet and give resolutions on theorder of 0.01 inches.

5. Radar and Laser Radar Detection and Identification of ObjectsExternal to the Vehicle

The RtZF system described herein can include an energy beam or floodthat is projected from the vehicle into the environment for the purposeof illuminating the environment around the vehicle and objects therein.In some cases this can be a beam of radar operating at 24 GHz or 77 GHz,for example. In other cases, this can be a laser beam in the infraredportion of the spectrum. Other frequencies can also be used and thereare particularly interesting developments in the terahertz frequencyrange. Terahertz devices are under development that can create aterahertz beam of radiation using laser technology. Similarly devicesare now available for sensing terahertz radiation with an array ofpixels. The terahertz frequency is interesting for interrogating thevicinity of a vehicle since it can be transmitted in a very narrow beamlike a laser and yet it has the ability to penetrate fog, for example,more like radar, but not nearly as good as radar, thus providing theadvantages of both systems. In the form of a flood light to illuminateareas closer to the vehicle for blind spot interrogation or for use as aheadlight for animal and pedestrian identification is also interestingsince such a system would work in both daylight and at night since thereis little natural radiation in the terahertz part of the electromagneticspectrum. When used as a beam, terahertz will be referred herein asterahertz radar. For the purposes herein, the terahertz frequency rangewill be taken as the range from about 300 GHz (0.3 THz) to about 3000GHz (3 THz) which is about where the infrared range begins.

Lasers, such as infrared lasers, can be used in beams of varyingdiameter and divergence angles through the appropriate optics providingthe energy of the beam per square millimeter remains below the eyesafety limits set by the U.S. Government. Thus, a very narrow beam canbe used in a scanning fashion, in which case, in the limit a singlepixel can be used as the detector such as a photodiode or avalanchediode. In other cases, a high-powered diode laser can still emitradiation below the eye safe limits if the beam is expanded throughappropriate optics, in which case, a multi-pixel detector such as a CCDor CMOS imager can be used. In both cases, a particular range from thevehicle can be interrogated and imaged, as discussed below herein,through range gating. Although this concept was originally disclosed inthe patents and patent applications referenced above and assigned to thecurrent assignee of this patent application, several recent patents andpublications have also disclosed some features. Some of these relatedart patents and publications will now be discussed.

One method of achieving range gating is disclosed in WO9701111 and thatpublication discloses other prior art range gating methods that havebeen used to obtain three dimensional information of a scene. Asmentioned elsewhere herein, other systems use liquid crystals, garnetcrystals, Pockel and Kerr cells. Prior to the disclosure in theassignee's patents, none of these methods have been used in theautomotive environment for obtaining three-dimensional information aboutobjects within or outside of a vehicle. Nevertheless, the use of theoptical ranging apparatus and techniques disclosed in this and otherpatents and publications of 3DV Systems Ltd. are among the preferredmethods used in practicing the teachings of the instant invention. Otherpatents and publications of 3DV include: WO9701112, WO9701113, U.S. Pat.No. 6,327,073, U.S. Pat. No. 6,483,094 and U.S. Pat. No. 20020185590.

U.S. Pat. No. 5,791,757, U.S. Pat. No. 5,857,770, U.S. Pat. No.5,890,796, U.S. Pat. No. 5,971,578 and U.S. Pat. No. 6,036,340 arepatents assigned to Ford Global Technologies, LLC relating to the use ofa high power laser diode in the visible portion of the spectrum forautomotive headlight and tail light application. These patents aresignificant in that they show how to implement such a device so thatlittle space is occupied. These patents do not disclose the use of alaser diode for interrogating the space adjacent to or at a distancefrom the vehicle for any purpose such as collision avoidance. The opticssystem illustrated could be usable in implementing one or more of theinventions disclosed herein as are other optical systems.

U.S. Pat. No. 6,690,017, also assigned to Ford Global Technologies, LLC,relates to the use of a high-power infrared laser diode in conjunctionwith a display for night vision applications. In order to avoid blindinga similar system of an approaching vehicle, the illumination created issynchronized based of the GPS clock and the direction that the vehicleis traveling. In at least one invention disclosed herein, the GPS clockis also utilized to control the time of transmission of an IRinterrogating illumination but since the distance to the object beinginterrogated in important, and since vehicles traveling in the samedirection as the subject vehicle may also have similar apparatus, thetransmission is synchronized so as not to interfere with such similarsystems as discussed below.

U.S. Pat. No. 6,725,139, also assigned to Ford Global Technologies, LLC,relates to a method of controlling the direction of infraredillumination based on the steering direction of the vehicle. This nightvision system is used in conjunction with a display to supplement thenormal headlights. Although inventions described herein disclosechanging the direction of projected illumination, in general it is nottied to the direction of the steering wheel.

U.S. Pat. No. 6,730,913, U.S. Pat. No. 6,774,367 and U.S. Pat. No.6,809,870, similarly assigned to Ford Global Technologies, LLC, describea night vision system using range gating to determine the location ofobjects in the field of view. The general disclosure of these patents isbelieved to be anticipated by assignee's patents referenced above. Thepatents describe three methods of obtaining equal illumination forvarying distances, varying the intensity of the transmitted pulses,varying the camera sensitivity or varying the number of pulses used tointerrogate a particular range. It is well known in the art that toobtain an image of sufficient brightness to permit display or imageanalysis, sufficient illumination must be supplied. These patents,however, purport to provide equal brightness for all objects regardlessof their distance from the camera. Also, these patents are based on theconcept that a series of gradually increasing ranges will always besequentially interrogated whereas in the instant invention theinterrogation method will not necessarily follow such a scheme and thelocation of the roadway as known from accurate maps will often be usedto determine the range and direction of the interrogating illumination.Another variable, not discussed in the '913 patent is the variation ofthe transmission angular field of view of the illumination as is used insome applications of the current invention discussed below. Further, atleast one of the current inventions disclosed herein can be used forilluminating and identifying objects external to the vehicle both indaytime and at night. Note also that the concept of triggeringillumination out of phase to prevent one vehicle's system frominterfering with another's as disclosed in the '367 patent waspreviously disclosed in assignee's patents and patent applications.

U.S. Pat. No. 6,429,429 and patent application publications U.S.20030034462, U.S. 20030036881 and U.S. 20030155513 also assigned to FordGlobal Technologies, LLC, describe various night vision systems some ofwhich use range gating and time-of-flight methods as first disclosed inthe assignee's patents cross referenced above.

A paper by Amamoto, Naohiro and Matsumoto, Koji entitled “ObstructionDetector By Environmental Adaptive Background Image Updating” describesa method for distinguishing between moving object pixels, stationaryobject pixels, and pixels that change due to illumination changes in avideo image. This paper appears to handle the case of a camera fixedrelative to the earth, not one mounted on a vehicle. This allows thesystem to distinguish between a congested area and an area where carsare moving freely. The video sampling rate was 100 milliseconds.

A paper by Doi, Ayumu, Yamamomo, Yasunori, and Butsuen, Tetsuro entitled“Development Of Collision Warning System and Its Collision AvoidanceEffect” describes a collision warning system that has twice the accuracyof conventional systems. It uses scanning a laser radar. In the systemdescribed in this paper, the authors do not appear to use phasemeasurements, range gating or time of flight to separate one vehiclefrom another.

A paper by Min, Joon, Cho, Hyung, and Choi, Jong, entitled “A LearningAlgorithm Using Parallel Neuron Model” describes a method of accuratelycategorizing vehicles based on the loop in the highway. This system usesa form of neural network, but not a back propagation neural network.This would essentially be categorizing a vehicle by its magneticsignature. Much information is lost in this system, however, due to thelack of knowledge of the vehicle's velocity.

Work has been done at JPL (Jet Propulsion Laboratories) to develop atarget recognition system. Neural networks play a key role in thistarget recognition process. The recognition of vehicles on a roadway isa considerably simpler process. Most of the cluttering information canbe eliminated through range gating. The three-dimensional image obtainedas described below will permit simple rotations of the image toartificially create a frontal view of the object being investigated.Also, the targets of interest here are considerably closer than wasconsidered by JPL. Nevertheless, the techniques described in thisreference and in the references cited by this reference, are applicablehere in a simplified form. The JPL study achieved over a 90% successrate at 60 frames per minute.

U.S. Pat. No. 4,521,861 to Logan describes a method and apparatus forenhancing radiometric in-aging and a method and apparatus for enhancingtarget detection through the utilization of an imaging radiometer. Theradiometer, which is a passive thermal receiver, detects the reflectedand emitted thermal radiation of targets. Prior to illumination, foliagewill appear hot due to its high emissivity and metals will appear colddue to their low emissivities. When the target is momentarilyilluminated foliage appears dark while metals appear hot. By subtractingthe non-illuminated image from the illuminated image, metal targets areenhanced. The teachings of this patent thus have applicability toembodiments of the instant invention as discussed below.

U.S. Pat. No. 5,463,384 to Juds uses a plurality of infrared beams toalert a truck driver that a vehicle is in his blind spot when he beginsto turn the vehicle. The system is typically activated by the vehicle'sturn signal. No attempt is made to measure exactly where the object is,only whether it is in the blind spot or not.

U.S. Pat. No. 5,467,072 to Michael relates to a phased array radarsystem that permits the steering of a radar beam without having torotate antennas. Aside from that, it suffers from all the disadvantagesof radar systems as described here. In particular, it is not capable ofgiving accurate three-dimensional measurements of an object on theroadway.

U.S. Pat. No. 5,486,832 to Hulderman employs millimeter wave radar andoptical techniques to eliminate the need for a mechanical scanningsystem. A 35-degree arc is illuminated in the azimuth direction and 6degrees in elevation. The reflected waves are separated into sixteenindependent, simultaneously overlapping 1.8 degree beams. Each beam,therefore, covers a width of about 3 feet at 100 feet distance from thevehicle, which is far too large to form an image of the object in thefield of view. As a result, it is not possible to identify the objectsin the field of view. All that is known is that an object exists. Also,no attempt has been made to determine whether the object is located onthe roadway or not. Therefore, this invention suffers from thelimitations of other radar systems.

U.S. Pat. No. 5,530,447 to Henderson, et al. shows a system used toclassify targets as threatening or non-threatening, depending on whetherthe target is moving relative to the ground. This system is only forvehicles in an adjacent lane and is primarily meant to protect againstblind-spot type accidents. No estimation is made by the system of theposition of the target vehicle or the threatening vehicle, only itsrelative velocity.

U.S. Pat. No. 5,576,972 to Harrison provides a good background of howneural networks are used to identify various objects. Although notdirectly related to intelligent transportation systems or toaccident-avoidance systems such as described herein, these techniqueswill be applied to embodiments of the invention described herein asdiscussed below.

U.S. Pat. No. 5,585,798 to Yoshioka, et al. uses a combination of a CCDcamera and a laser radar unit. The invention attempts to make a judgmentas to the danger of each of the many obstacles that are detected. Theload on the central processor is monitored by looking at differentobstacles with different frequencies depending on their danger to thepresent system. A similar arrangement is contemplated for embodiments ofthe invention as disclosed herein.

U.S. Pat. No. 5,767,953 to McEwan describes a laser tape measure formeasuring distance. It is distinct from laser radars in that the widthof the pulse is measured in sub-nanosecond times, whereas laser radarsare typically in the microsecond range. The use of this technology inthe current invention would permit a much higher scanning rate than byconvention radar systems and thus provide the opportunity for obtainingan image of the obstructions on the highway. It is also less likely thatmultiple vehicles having the same system would interfere with eachother. For example, if an area 20 feet by 5 feet were scanned with a 0.2inch pixel size, this would give about one million pixels. If usinglaser radar, one pixel per microsecond is sent out, it would take onesecond to scan the entire area during which time the vehicle hastraveled 88 feet at 60 miles an hour. On the other hand, if scanningthis array at 100 feet, it would take 200 nanoseconds for the light totravel to the obstacle and back. Therefore, if a pulse is sent out everyfifth of a microsecond, it will take a fifth of a second to obtain amillion pixels, during which time the vehicle has traveled about 17feet. If 250,000 pixels are used, the vehicle will only have traveledabout 4 feet.

U.S. Pat. No. 4,352,105 and U.S. Pat. No. 4,298,280 to Harney describean infrared radar system and a display system for use by aircraft. Inparticular, these patents describe an infrared radar system thatprovides high resolution, bad weather penetration, day-night operationand which can provide simultaneous range, intensity and high resolutionangular information. The technology uses CO₂ laser and a 10.6 micronheterodyne detection. It is a compact imaging infrared radar system thatcan be used with embodiments of the invention described herein. Harneyapplies this technology to aircraft and does not contemplate itsapplication to collision avoidance or for other uses with land-basedvehicles such as automobiles.

Although, there appears not to be any significant prior art involving avehicle communicating safety information to another vehicle on theroadway, several patents discuss methods of determining that a collisionmight take place using infrared and radar. U.S. Pat. No. 5,249,128 toMarkandey et al., for example, discusses methods of using infrared todetermine the distance to a vehicle in front and U.S. Pat. No. 5,506,584to Boles describes a radar-based system. Both systems suffer from a highfalse alarm rate and could be substantially improved if a patternrecognition system such as neural networks were used. Also, neithersystem makes use of noise modulation technologies as taught herein.

6. Smart Highways

A paper entitled “Precursor Systems Analyses of Automated HighwaySystems (Executive Summary)” discusses that “an AHS (automated highwaysystem) can double or triple the efficiency of today's most congestedlanes while significantly increasing safety and trip quality”.

There are one million, sixty-nine thousand, twenty-two miles of pavednon-local roads in the US. Eight hundred twenty-one thousand and fourmiles of these are classified as “rural” and the remaining two hundredforty-eight thousand, eighteen miles are “urban”.

The existing interstate freeway system consists of approximately 50,000miles which is 1% of the total of 3.8 million miles of roads. Freewaysmake up 3% of the total urban/suburban arterial mileage and carryapproximately 30% of the total traffic.

In one study, dynamic route guidance systems were targeting at reducingtravel time of the users by 4%. Under the system of this invention, thetravel times would all be known and independent of congestion once avehicle had entered the system. Under the current system, the dynamicdelays can change measurably after a vehicle is committed to a specificroute. According to the Federal Highway Administration IntelligentTransportation Systems (ITS Field Operational Test), dynamic routeguidance systems have not been successful.

There are several systems presented in the Federal HighwayAdministration Intelligent Transportation Systems (ITS Field OperationalTest) for giving traffic information to commuters, called “AdvanceTraveler Information System” (ATIS). In none of these articles does itdiscuss the variation in travel time during rush hour for example, fromone day to the next. The variability in this travel time would have tobe significant to justify such a system. A system of this type would beunnecessary in situations where embodiments of the instant invention hasbeen deployed. The single most important cause of variability from dayto day is traffic incidents such as accidents, which are eliminated orat least substantially reduced by the instant invention. One of theconclusions in a study published in the “Federal Highway AdministrationIntelligent Transportation Systems (ITS Field Operational Test)”entitled “Direct Information Radio Using Experimental CommunicationTechnologies” was that drivers did not feel that the system was asignificant advance over commercial radio traffic information. They didthink the system was an improvement over television traffic informationand changeable message signs. The drivers surveyed on average havingchanged their route only one time in the eight week test period due toinformation they received from the system.

7. Weather and Road Condition Monitoring

A paper by Miyata, Yasuhiro and Otomo, Katsuya, Kato, Haijime, Imacho,Nobuhiro, Murata, Shigeo, entitled “Development of Road Icing PredictionSystem” describes a method of predicting road icing conditions severalhours in advance based on an optical fiber sensor laid underneath theroad and the weather forecast data of that area.

There is likely a better way of determining ice on the road thandescribed in this paper. The reflection of an infrared wave off the roadvaries significantly depending on whether there is ice on the road orsnow, or the road is wet or dry. A neural network could be a bettersolution. The system of this paper measures the road surfacetemperature, air temperature and solar radiation. A combination ofactive and passive infrared would probably be sufficient. Perhaps, aspecially designed reflective surface could be used on the road surfacein an area where it is not going to be affected by traffic.

What this paper shows is that if the proper algorithm is used, theactual road temperature can be predicted without the need to measure theroad surface temperature. This implies that icing conditions can bepredicted and the sensors would not be necessary. Perhaps, a neuralnetwork algorithm that monitors a particular section of road andcompares it to the forecasted data would be all that is required. Inother words, given certain meteorological data, the neural network oughtto be able to determine the probability of icing. What is needed,therefore, is to pick a section of roadway and monitor that roadway witha state-owned vehicle throughout the time period when icing is likely tooccur and determine if icing has occurred and compare that with themeteorological data using a neural network that is adapted for eachsection of road.

8. Communication with Other Vehicles

The RtZF™ system of this invention can incorporate vehicle-to-vehiclecommunication allowing vehicles to inform other vehicles of theirlocation, velocity, mass etc.

U.S. Pat. No. 5,506,584 to Boles relates to a system for communicationbetween vehicles through a transmit and transponder relationship. Thepatent mentions that there may be as many as 90 vehicles within one halfmile of an interrogation device in a multi-lane environment, where manyof them may be at the same or nearly the same range. Boles utilizes atransponder device, the coded responses which are randomized in time,and an interrogation device which processes the return signals toprovide vehicle identification, speed, location and transponder statusinformation on vehicles to an operator or for storage in memory. Nomention is made of how a vehicle knows its location or how accurate thatknowledge is and therefore how it can transmit that location to othervehicles.

U.S. Pat. No. 5,128,669 to Dabbs provides for two-way communication andaddressing messages to specific vehicles. This is unnecessary and thecommunications can be general since the amount of information that isunique to one vehicle is small. A method of handing bidirectionalcommunication is discussed in U.S. Pat. No. 5,506,584 to Boles. Thepreferred vehicle-to-vehicle communication system using pseudonoisetechniques is more thoroughly discussed below.

In embodiments of the invention described herein, vehicle-to-vehiclecommunication is used, among other purposes, to allow the fact that onevehicle knows its position more accurately than another to usecommunication to cause the other vehicle to also improve the accuracywith which it knows its position.

9. Infrastructure-to-Vehicle Communication

The RtZF™ system of this invention can also incorporate communicationbetween a vehicle and infrastructure for a variety of reasons includingobtaining the latest map updates, weather conditions, road conditions,speed limits, sign contents, accidents ahead, congestion ahead,construction, general Internet access and for many other reasons.

The DGPS correction information can be broadcast over the radio datasystem (RDS) via FM transmitters for land use. A company calledDifferential Correction, Inc. has come up with a technique to transmitthis DGPS information on the RDS channel. This technique has been usedin Europe since 1994 and, in particular, Sweden has launched anationwide DPGS service via the RDS (see, Sjoberg, Lars, “A ‘1 Meter’Satellite Based Navigation Solutions for the Mobile Environment ThatAlready Are Available Throughout Europe”). This system has the potentialof providing accuracies on the premium service of between about 1 and 2meters. A 1 meter accuracy, coupled with the carrier phase system to bedescribed below, provides an accuracy substantially better than about 1meter as preferred in the Road to Zero Fatalities™ (RtZF™) system ofthis invention.

In addition to the FM RDS system, the following other systems can beused to broadcast DGPS correction data: cellular mobile phones,satellite mobile phones, satellite Internet, WiFi, WiMAX, MCA(multi-channel access), wireless tele-terminals, DARCs/RBDS (radio datasystems/radio broadcast data system), type FM sub-carrier, exclusivewireless, and pagers. In particular, DARC type is used for vehicleinformation and communication systems so that its hardware can beshared. Alternately, the cellular phone system, coupled with theInternet, could be used for transmitting corrections (see, Ito, Toru andNishiguchi, Hiroshi entitled “Development of DGPS using FM Sub-CarrierFor ITS”). Primarily, as discussed elsewhere, vehicle-to-vehiclecommunications can be used to transmit DGPS corrections from one vehicleto another whether the source is a central DGPS system or one based onPPS or other system.

One approach for the cellular system is to use the GSM mobile telephonesystem, which is the Europe-wide standard. This can be used fortransmitting DGPS and possibly map update information (see, Hob, A.,Ilg, J. and Hampel, A. entitled “Integration Potential Of TrafficTelematics).

In Choi, Jong and Kim, Hoi, “An Interim Report: Building A WirelessInternet-Based Traveler's Information System As A Replacement Of CarNavigation Systems”, a system of showing congestion at intersections isbroadcast to the vehicle through the Internet. The use of satellites isdiscussed as well as VCS system.

This is another example of the use of the Internet to provide highwayusers with up-to-date traffic congestion information. Nowhere in thisexample, however, is the Internet used to transmit map information. Infact, once there is an Internet or equivalent connection to a vehicle,then other information can be transmitted such as updated mapinformation, weather and visibility, local conditions ahead, accidentinformation, congestion information, DGPS corrections, etc. In fact,with a high bandwidth Internet connection, much of the computations,especially safety related computations, can best be done on the Internetwhere the system reliability would exceed that of a vehicle-basedsystem. The forecast that “the network is the computer” will begin tobecome reality. The crash of a safety related processor due to asoftware bug could not be tolerated in a safety related system and wouldbe less likely to occur if the critical computations occur on thenetwork. Furthermore, upgrades to vehicle-based software also becomefeasible over such a high bandwidth connection.

A paper by Sheu, Dennis, Liaw, Jeff and Oshizawa, Al, entitled “ACommunication System For In-Vehicle Navigation System” provides anotherdescription of the use of the Internet for real traffic information.However, the author (unnecessarily) complicates matters by using pushtechnology which isn't absolutely necessary and with the belief that theInternet connection to a particular vehicle to allow all vehicles tocommunicate, would have to be stopped which, of course, is not the case.For example, consider the @home network where everyone on the network isconnected all the time.

A paper by Rick Schuman entitled “Progress Towards ImplementingInteroperable DSRC Systems In North America” describes the standards fordedicated short-range communications (DSRC). DSRC could be used forinter-vehicle communications, however, its range according to the ITSproposal to the Federal Government would be limited to about 90 metersalthough there have been recent proposals to extend this to about 1000meters. Also, there may be a problem with interference from tollcollection systems, etc. According to this reference, however, “it islikely that any widespread deployment of intersection collisionavoidance or automated highways would utilize DSRC”. Ultra wide bandcommunication systems, on the other hand, are a viable alternative toDSRC as explained below. The DSRC physical layer uses microwaves in the902 to 928 megahertz band. However, ITS America submitted a petition tothe FCC seeking to use the 5.85 to 5.925 gigahertz band for DSRCapplications.

A version of CDPD, which is a commercially available mobile, wirelessdata network operated in the packet-switching mode, extends Internetprotocol capabilities to cellular channels. This is reported on in apaper entitled “Intelligent Transportation Systems (ITS) Opportunity”.

According to a paper by Kelly, Robert, Povich, Doublas and Poole,Katherine entitled “Petition of Intelligent Transportation Society ofAmerica for Amendment Of The Commission's Rules to Add IntelligentTransportation Services (ITS) As A New Mobile Service With Co-PrimaryStatus In The 5.850 to 5.925 GHz”, from 1989 to 1993 police received anannual average of over 6.25 million vehicle accident reports. Duringthis same period, the total comprehensive cost to the nation of motorvehicle accidents exceeded the annual average of 400 billion dollars. In1987 alone, Americans lost over 2 billion hours (approximately 22,800years) sitting in traffic jams. Each driver in Washington D.C. wastes anaverage of 70 hours per year idling in traffic. From 1986 to 1996, cartravel has increased almost 40% which amounts to about a 3.4% increaseper year.

Further, from Kelly et al., the FCC has allocated in Docket 94–124, 46.7to 46.9 GHz and 76 to 77 GHz bands for unlicensed vehicular collisionavoidance radar. The petition for DSRC calls for a range of up to about50 meters. This would not be sufficient for the RtZF™ system. Forexample, in the case of a car passing another car at 150 kilometers perhour. Fifty meters amounts to about one second, which would beinsufficient time for the passing vehicle to complete the passing andreturn to the safe lane. Something more in the order of about 500 meterswould be more appropriate. This, however, may interfere with other usesof DSRC such as automatic toll taking, etc., thus DSRC may not be theoptimum communication system for communication between vehicles. DSRC isexpected to operate at a data rate of approximately 600 kbps. DSRC isexpected to use channels that are six megahertz wide. It might bepossible to allocate one or more of the six megahertz channels to theRtZF™ system.

On DSRC Executive Roundtable—Meeting Summary, Appendix 1—ProposedChanges to FCC Regulations covering the proposed changes to the FCCregulations, it is stated that “ . . . DSRCS systems utilize non-voiceradio techniques to transfer data over short distances between roadsideand mobile units, between mobile units and between portable and mobileunits to perform operations related to the improvement of traffic flow,traffic safety and other intelligent transportation service applications. . . ”, etc.

A state or the Federal Government may require in the future that allvehicles have passive transponders such as RFID tags. This could be partof the registration system for the vehicle and, in fact, could even bepart of the license plate. This is somewhat discussed in a paper byShladover, Steven entitled “Cooperative Advanced Vehicle Control andSafety Systems (AVCSS)”. AVCSS sensors will make it easy to detect thepresence, location and identity of all other vehicles in their vicinity.Passive radio frequency transponders are discussed. The use ofdifferential GPS with accuracies as good as about two (2) centimeters,coupled with an inertial guidance system, is discussed, as is theability of vehicles to communicate their locations to other vehicles. Itdiscusses the use of accurate maps, but not of lateral vehicle controlusing these maps. It is obvious from reading this paper that the authordid not contemplate the safety system aspects of using accurate maps andaccurate GPS. In fact, the author stresses the importance of cooperationbetween various government levels and agencies and the private sector inorder to make AVCSS feasible. “Automotive suppliers cannot sellinfrastructure-dependent systems to their customers until the very largemajority of the infrastructure is suitable equipped.”

10. The RtZF™ System—Intelligent Transportation Infrastructure Benefits

A paper entitled “Intelligent Transportation Infrastructure Benefits:Expected and Experienced”, 1996 US Department of Transportation,provides a summary of costs and benefits associated with very modest ITSimplementations. Although a complete cost benefit analysis has not beenconducted on the instant invention, it is evident from reading thispaper that the benefits to cost ratio will be a very large number.

According to this paper, the congestion in the United States isincreasing at about 9% per year. In 50 metropolitan areas, the cost in1992 was estimated at 48 billion dollars and in Washington, D.C., itrepresented an annual cost of $822 per person, or $1,580 per registeredvehicle. In 1993, there were 40,115 people killed and 3 million injuredin traffic accidents. Sixty-one percent (61%) of all fatal accidentsoccurred in rural areas. This reference lists the 29 user services thatmake up the ITS program. It is interesting that the instant inventionprovides 24 of the 29 listed user services. A listing of the servicesand their proposed implementation with the RtZF™ system is found in U.S.patent application Ser. No. 10/822,445, now U.S. Pat. No. 7,085,637, andis incorporated by reference herein.

The above references, among other things, demonstrate that there arenumerous methods and future enhancements planned that will providecentimeter level accuracy to an RtZF™ equipped vehicle. There are manyalternative paths that can be taken but which ever one is chosen theresult is clear that such accuracies are within the start of the arttoday.

In the particular area of speed control, U.S. Pat. No. 5,530,651 toUemura, et al. describes a combination of an ultrasonic and laser radaroptical detection system which has the ability to detect soiled lenses,rain, snow, etc. The vehicle control system then automatically limitsthe speed, for example, that the vehicle can travel in adverse weatherconditions. The speed of the vehicle is also reduced when the visibilityahead is reduced due to a blind, curved corner. The permitted speed isthus controlled based on weather conditions and road geometry. There isno information in the vehicle system as to the legal speed limit asprovided for in embodiments of the instant invention.

11. Limitations of the Prior Art

Previous inventions have attempted to solve the collision avoidanceproblem for each vehicle independently of the other vehicles on theroadway. Systems that predict vehicle trajectories generally failbecause two vehicles can be on a collision course and within the last0.1 second, a slight change of direction avoids the collision. This is acommon occurrence that depends on the actions of the individual driversand no collision avoidance system now in existence is believed to beable to differentiate this case from an actual collision. In the presentinvention described below, every equipped vehicle will be confined to acorridor and to a position within that corridor where the corridordepends on sub-meter accurate digital maps. Only if that vehicledeviates from the corridor will an alarm sound or the vehicle controlsystem take over control of the vehicle sufficiently to prevent thevehicle from leaving its corridor if an accident would result from thedeparture from that corridor.

Additionally, no prior art system is believed to have successfully usedthe GPS navigational system, or an augmented DGPS to locate a vehicle ona roadway with sufficient accuracy that that information can be used toprevent the equipped vehicle from leaving the roadway or strikinganother similarly equipped vehicle.

Prior art systems in addition to being poor at locating potentialhazards on the roadway, have not been able to ascertain whether they arein fact on the roadway or off on the side, whether they are threateningvehicles, static signs, overpasses etc. In fact, no credible attempt todate has been made to identify or categorize objects which may impactthe subject vehicle.

The RtZF™ system in accordance with this invention also contemplates adifferent kind of interrogating system. It is optionally based onscanning infrared laser radar, terahertz radar with or without rangegating. This system, when used in conjunction with accurate maps, willpermit a precise imaging of an object on the road in front of thevehicle, for example, permitting it to be identified (using neuralnetworks) and its location, velocity and the probability of a collisionto be determined.

In particular, the system of this invention is particularly effective ineliminating accidents at intersections caused by drivers running stopsigns, red stoplights and turning into oncoming traffic. There areapproximately one million such accidents and they are the largest killerof older drivers who frequently get confused at intersections.

12. Definitions

“Pattern recognition” as used herein will generally mean any systemwhich processes a signal that is generated by an object (e.g.,representative of a pattern of returned or received impulses, waves orother physical property specific to and/or characteristic of and/orrepresentative of that object) or is modified by interacting with anobject, in order to determine to which one of a set of classes that theobject belongs. Such a system might determine only that the object is oris not a member of one specified class, or it might attempt to assignthe object to one of a larger set of specified classes, or find that itis not a member of any of the classes in the set. The signals processedare generally a series of electrical signals coming from transducersthat are sensitive to acoustic (ultrasonic) or electromagnetic radiation(e.g., visible light, infrared radiation, capacitance or electric and/ormagnetic fields), although other sources of information are frequentlyincluded. Pattern recognition systems generally involve the creation ofa set of rules that permit the pattern to be recognized. These rules canbe created by fuzzy logic systems, statistical correlations, or throughsensor fusion methodologies as well as by trained pattern recognitionsystems such as neural networks, combination neural networks, cellularneural networks or support vector machines.

“Neural network” as used herein, unless stated otherwise, will generallymean a single neural network, a combination neural network, a cellularneural network, a support vector machine or any combinations thereof.For the purposes herein, a “neural network” is defined to include allsuch learning systems including cellular neural networks, support vectormachines and other kernel-based learning systems and methods, cellularautomata and all other pattern recognition methods and systems thatlearn. A “combination neural network” as used herein will generallyapply to any combination of two or more neural networks as most broadlydefined that are either connected together or that analyze all or aportion of the input data.

A “combination neural network” as used herein will generally apply toany combination of two or more neural networks that are either connectedtogether or that analyze all or a portion of the input data. Acombination neural network can be used to divide up tasks in solving aparticular object sensing and identification problem. For example, oneneural network can be used to identify an object occupying a space atthe side of an automobile and a second neural network can be used todetermine the position of the object or its location with respect to thevehicle, for example, in the blind spot. In another case, one neuralnetwork can be used merely to determine whether the data is similar todata upon which a main neural network has been trained or whether thereis something significantly different about this data and therefore thatthe data should not be analyzed. Combination neural networks cansometimes be implemented as cellular neural networks.

What has been described above is generally referred to as modular neuralnetworks with and without feedback. Actually, the feedback does not haveto be from the output to the input of the same neural network. Thefeedback from a downstream neural network could be input to an upstreamneural network, for example.

The neural networks can be combined in other ways, for example in avoting situation. Sometimes the data upon which the system is trained issufficiently complex or imprecise that different views of the data willgive different results. For example, a subset of transducers may be usedto train one neural network and another subset to train a second neuralnetwork etc. The decision can then be based on a voting of the parallelneural networks, sometimes known as an ensemble neural network. In thepast, neural networks have usually only been used in the form of asingle neural network algorithm for identifying the occupancy state ofthe space near an automobile. At least one of the inventions disclosedherein is primarily advancing the state of the art and using combinationneural networks wherein two or more neural networks are combined toarrive at a decision.

The applications for this technology are numerous as described in thepatents and patent applications listed above. However, the main focus ofsome of the instant inventions is the process and resulting apparatus ofadapting the system in the patents and patent applications referencedabove and using combination neural networks for the detection of thepresence of an object such as another vehicle in the environment of thesubject vehicle where an accident may occur and the motion of thevehicle needs to be controlled so as to prevent such an accident.

A trainable or a trained pattern recognition system as used hereingenerally means a pattern recognition system that is taught to recognizevarious patterns constituted within the signals by subjecting the systemto a variety of examples. The most successful such system is the neuralnetwork used either singly or as a combination of neural networks. Thus,to generate the pattern recognition algorithm, test data is firstobtained which constitutes a plurality of sets of returned waves, orwave patterns, or other information radiated or obtained from an object(or from the space in which the object will be situated in the passengercompartment, i.e., the space above the seat) and an indication of theidentify of that object. A number of different objects are tested toobtain the unique patterns from each object. As such, the algorithm isgenerated, and stored in a computer processor, and which can later beapplied to provide the identity of an object based on the wave patternbeing received during use by a receiver connected to the processor andother information. For the purposes here, the identity of an objectsometimes applies to not only the object itself but also to its locationand/or orientation and velocity in the vicinity of the vehicle. Forexample, a vehicle that is stopped but pointing at the side of the hostvehicle is different from the same vehicle that is approaching at such avelocity as to impact the host vehicle. Not all pattern recognitionsystems are trained systems and not all trained systems are neuralnetworks. Other pattern recognition systems are based on fuzzy logic,sensor fusion, Kalman filters, correlation as well as linear andnon-linear regression. Still other pattern recognition systems arehybrids of more than one system such as neural-fuzzy systems.

A pattern recognition algorithm will thus generally mean an algorithmapplying or obtained using any type of pattern recognition system, e.g.,a neural network, sensor fusion, fuzzy logic, etc.

To “identify” as used herein will generally mean to determine that theobject belongs to a particular set or class. The class may be onecontaining, for example, all motorcycles, one containing all trees, orall trees in the path of the host vehicle depending on the purpose ofthe system.

To “ascertain the identity of” as used herein with reference to anobject will generally mean to determine the type or nature of the object(obtain information as to what the object is), i.e., that the object isan car, a car on a collision course with the host vehicle, a truck, atree, a pedestrian, a deer etc.

A “rear seat” of a vehicle as used herein will generally mean any seatbehind the front seat on which a driver sits. Thus, in minivans or otherlarge vehicles where there are more than two rows of seats, each row ofseats behind the driver is considered a rear seat and thus there may bemore than one “rear seat” in such vehicles. The space behind the frontseat includes any number of such rear seats as well as any trunk spacesor other rear areas such as are present in station wagons.

An “optical image” will generally mean any type of image obtained usingelectromagnetic radiation including visual, infrared, terahertz andradar radiation.

In the description herein on anticipatory sensing, the term“approaching” when used in connection with the mention of an object orvehicle approaching another will usually mean the relative motion of theobject toward the vehicle having the anticipatory sensor system. Thus,in a side impact with a tree, the tree will be considered as approachingthe side of the vehicle and impacting the vehicle. In other words, thecoordinate system used in general will be a coordinate system residingin the target vehicle. The “target” vehicle is the vehicle that is beingimpacted. This convention permits a general description to cover all ofthe cases such as where (i) a moving vehicle impacts into the side of astationary vehicle, (ii) where both vehicles are moving when theyimpact, or (iii) where a vehicle is moving sideways into a stationaryvehicle, tree or wall.

“Vehicle” as used herein includes any container that is movable eitherunder its own power or using power from another vehicle. It includes,but is not limited to, automobiles, trucks, railroad cars, ships,airplanes, trailers, shipping containers, barges, etc. The word“container” will frequently be used interchangeably with vehicle howevera container will generally mean that part of a vehicle that separatefrom and in some cases may exist separately and away from the source ofmotive power. Thus a shipping container may exist in a shipping yard anda trailer may be parked in a parking lot without the tractor. Thepassenger compartment or a trunk of an automobile, on the other hand,are compartments of a container that generally only exists attaches tothe vehicle chassis that also has an associated engine for moving thevehicle. Note a container can have one or a plurality of compartments.

“Out-of-position” as used for an occupant will generally mean that theoccupant, either the driver or a passenger, is sufficiently close to anoccupant protection apparatus (airbag) prior to deployment that he orshe is likely to be more seriously injured by the deployment eventitself than by the accident. It may also mean that the occupant is notpositioned appropriately in order to attain the beneficial, restrainingeffects of the deployment of the airbag. As for the occupant being tooclose to the airbag, this typically occurs when the occupant's head orchest is closer than some distance such as about 5 inches from thedeployment door of the airbag module. The actual distance where airbagdeployment should be suppressed depends on the design of the airbagmodule and is typically farther for the passenger airbag than for thedriver airbag.

“Transducer” or “transceiver” as used herein will generally mean thecombination of a transmitter and a receiver. In come cases, the samedevice will serve both as the transmitter and receiver while in otherstwo separate devices adjacent to each other will be used. In some cases,a transmitter is not used and in such cases transducer will mean only areceiver. Transducers include, for example, capacitive, inductive,ultrasonic, electromagnetic (antenna, CCD, CMOS arrays, laser, radartransmitter, terahertz transmitter and receiver, focal plane array, pinor avalanche diode, etc.), electric field, weight measuring or sensingdevices. In some cases, a transducer will be a single pixel eitheracting alone, in a linear or an array of some other appropriate shape.In some cases, a transducer may comprise two parts such as the plates ofa capacitor or the antennas of an electric field sensor. Sometimes, oneantenna or plate will communicate with several other antennas or platesand thus for the purposes herein, a transducer will be broadly definedto refer, in most cases, to any one of the plates of a capacitor orantennas of a field sensor and in some other cases a pair of such platesor antennas will comprise a transducer as determined by the context inwhich the term is used.

“Adaptation” as used here will generally represent the method by which aparticular occupant or vehicle or other object sensing system isdesigned and arranged for a particular vehicle model. It includes suchthings as the process by which the number, kind and location of varioustransducers is determined. For pattern recognition systems, it includesthe process by which the pattern recognition system is designed and thentaught or made to recognize the desired patterns. In this connection, itwill usually include (1) the method of training when training is used,(2) the makeup of the databases used, testing and validating theparticular system, or, in the case of a neural network, the particularnetwork architecture chosen, (3) the process by which environmentalinfluences are incorporated into the system, and (4) any process fordetermining the pre-processing of the data or the post processing of theresults of the pattern recognition system. The above list isillustrative and not exhaustive. Basically, adaptation includes all ofthe steps that are undertaken to adapt transducers and other sources ofinformation to a particular vehicle to create the system that accuratelyidentifies and/or determines the location of an occupant or other objectin a vehicle or in the environment around the vehicle.

A “morphological characteristic” will generally mean any measurableproperty of a human such as height, weight, leg or arm length, headdiameter, skin color or pattern, blood vessel pattern, voice pattern,finger prints, iris patterns, etc.

A “wave sensor” or “wave transducer” is generally any device whichsenses either ultrasonic or electromagnetic waves. An electromagneticwave sensor, for example, includes devices that sense any portion of theelectromagnetic spectrum from ultraviolet down to a few hertz. The mostcommonly used kinds of electromagnetic wave sensors include CCD and CMOSarrays for sensing visible and/or infrared waves, millimeter wave andmicrowave radar, and capacitive or electric and/or magnetic fieldmonitoring sensors that rely on the dielectric constant of the objectoccupying a space but also rely on the time variation of the field,expressed by waves as defined below, to determine a change in state.

A “CCD” will be defined to include all devices, including CMOS arrays,APS arrays, QWIP arrays or equivalent, artificial retinas andparticularly HDRC arrays, which are capable of converting lightfrequencies, including infrared, visible and ultraviolet, intoelectrical signals. The particular CCD array used for many of theapplications disclosed herein is implemented on a single chip that isless than two centimeters on a side. Data from the CCD array isdigitized and sent serially to an electronic circuit (at timesdesignated 120 herein) containing a microprocessor for analysis of thedigitized data. In order to minimize the amount of data that needs to bestored, initial processing of the image data takes place as it is beingreceived from the CCD array, as discussed in more detail above. In somecases, some image processing can take place on the chip such asdescribed in the Kage et al. artificial retina article referenced above.

The “windshield header” as used herein includes the space above thefront windshield including the first few inches of the roof.

An “occupant protection apparatus” is any device, apparatus, system orcomponent which is actuatable or deployable or includes a componentwhich is actuatable or deployable for the purpose of attempting toreduce injury to the occupant in the event of a crash, rollover or otherpotential injurious event involving a vehicle Inertial measurement unit(IMU), inertial navigation system (INS) and inertial reference unit(IRU) will in general be used be used interchangeably to mean a devicehaving a plurality of accelerometers and a plurality of gyroscopesgenerally within the same package. Usually such a device will contain 3accelerometers and 3 gyroscopes. In some cases a distinction will bemade whereby the INS relates to an IMU or an IRU plus additional sensorsand software such as a GPS, speedometer, odometer or other sensors plusoptimizing software which may be based on a Kalman filter.

A precise positioning system or PPS is a system based on someinformation, usually of a physical nature, in the infrastructure thatdetermines the precise location of a vehicle independently of a GPSbased system or the IMU. Such a system is employed as a vehicle istraveling and passes a particular location. A PPS can make use ofvarious technologies including radar, laser radar, terahertz radar, RFIDtags located in the infrastructure, MIR transmitters and receivers. Suchlocations are identified on a map database resident within the vehicle.In one case, for example, the map database contains data from aterahertz radar continuous scan of the environment to the side of avehicle from a device located on a vehicle and pointed 45 degrees uprelative to the horizontal plane. The map database contains the exactlocation of the vehicle that corresponds to the scan. Another vehiclecan then determine its location by comparing its scan data with thatstored with the map database and when there is a match, the vehicleknows its location. Of course many other technologies can be used toaccomplish a similar result.

Unless stated otherwise, laser radar, lidar and ladar will be consideredequivalent herein. In all cases they represent a projected laser beam,which can be in the visual part of the electromagnetic spectrum butgenerally will be the infrared part of the electromagnetic spectrum andusually in the near infrared wavelengths. The projected laser beam canemanate from the optics as a nearly parallel beam or as a beam thatdiverges at any desired angle from less than zero degrees to ten or moreof degrees depending on the application. A particular implementation mayuse a laser beam that at one time diverges at an angle less than onedegree and at another time may diverge at several degrees usingadjustable optics. The laser beam can have a diameter as it leaves thevehicle ranging from less than a millimeter to several centimeters. Theabove represent typical or representative ranges of dimensions but thisinvention is not limited by these ranges.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and improvedmethod for obtaining information about objects in the environmentoutside of and around a vehicle.

It is another object of the present invention to provide a new andimproved method and system for avoiding collisions between a vehicle andanother object, such as another vehicle or infrastructure.

In order to achieve these objects and others, a method for obtaininginformation about objects in the environment outside of and around avehicle includes directing a laser beam from the vehicle into theenvironment, receiving from an object in the path of the laser beam areflection of the laser beam at a location on the vehicle, and analyzingthe received laser beam reflections to obtain information about theobject from which the laser beam is being reflected. Analysis of thelaser beam reflections preferably entails range gating the receivedlaser beam reflections to limit analysis of the received laser beamreflections to only those received from an object within a defined(distance) range such that objects at distances within the range areisolated from surrounding objects. In this manner, data gathering isoptimized in that data about only objects in the distance range isobtained.

To optimize the method, the direction of the laser beam can becontrolled to cover only a desired operating sector. Also, so thatobjects that cannot potentially impact the vehicle are not considered,thereby reducing wasted processing time for the processor and falsealerts, a digital map may be provided including information relating toroads on which the vehicle can travel or is traveling. In this manner,objects which cannot impact the vehicle, such as those traveling on thesame road but in an opposite direction and when a concrete barrierseparates the lanes, are not considered potentially dangerous. A fieldinto which the laser beam will be directed is defined based on the mapand the laser beam is directed primarily only into the defined field.

To cover possible situations with curved roads causing the vehicle tocurve, two laser beams can be directed into the environment. The laserbeams can have different scanning speeds.

Analysis of the laser beam reflections may also entail analyzing thereceived laser beam reflections to detect the presence of objectspotentially affecting operation of the vehicle, e.g., which wouldrequire the vehicle to alter its travel path to avoid a collision withthe vehicle. Range gating is performed once the presence of each objectis detected and the range is determined to encompass any objects whosepresence has been detected. The range can be narrowed such that laserbeam reflections from only the object whose presence is detected andother objects in the same range are analyzed and processed to obtainidentification or identity information about them. Pattern recognitionalgorithms can be used to process the received laser beam reflections,e.g., to ascertain the identity of or identity the objects. If an objectis identified and the potential for a collision between the vehicle andthat object is determined to be present, the driver can be alerted aboutthe potential collisions, e.g., visually and/or audibly, and/or avehicle control system can be activated to alter the vehicle's travelpath to avoid the collision.

A method for avoiding collisions between a vehicle and another objectincludes mounting a laser beam projector on the vehicle, directing alaser beam from the projector outward from the vehicle, determiningwhether an object is present in the path of the laser beam based onreception of reflections of the laser beam caused by the presence of theobject in the path of the laser beam, and when an object is determinedto be present, setting a distance range including a distance between thevehicle and the object, processing only received reflections of thelaser beam emanating from objects in the set distance range to determinewhether each object may impact the vehicle, and if a determination ismade that the object may impact the vehicle, effecting a countermeasurewith a view toward preventing the collision. The same enhancements tothe method described above can be applied here as well, e.g., the use ofa digital map to limit the number of objects considered as potentiallydangerous and the countermeasures effected to avoid collisions.

A system for avoiding collisions between a vehicle and another objectincludes a laser beam projector arranged on the vehicle to directing alaser beam outward from the vehicle, a receiving unit for receivingreflections of the laser beam which reflect off of objects in the pathof the laser beam, and a control unit, module or processor arranged toprocess any received reflections to determine whether an object ispresent in the path of the laser beam. When an object is determined tobe present, the processor sets a distance range including a distancebetween the vehicle and the object, processes only received reflectionsof the laser beam emanating from objects in the set distance range todetermine whether each object may impact the vehicle, and if adetermination is made that the object may impact the vehicle, causes acountermeasure to be effected with a view toward preventing thecollision. Optionally, the processor includes a pattern recognitionalgorithm which ascertains the identity of or identifies each object inthe set distance range and assesses the potential for and consequencesof a collision between the vehicle and the object based on the identityor identification of the object. The countermeasures can be activationof a driver notification system to alert the driver of the impendingcollision or activation of a vehicle control system to vary the travelof the vehicle to avoid the impending collision.

Other objects and advantages of disclosed inventions include:

-   1. To provide a system based partially on the global positioning    system (GPS) or equivalent that permits an onboard electronic system    to determine the position of a vehicle with an accuracy of 1 meter    or less.-   2. To provide a system which permits an onboard electronic system to    determine the position of the edges and/or lane boundaries of a    roadway with an accuracy of 1 meter or less in the vicinity of the    vehicle.-   3. To provide a system which permits an onboard vehicle electronic    system to determine the position of the edges and/or lane boundaries    of a roadway relative to the vehicle with an accuracy of less than    about 10 centimeters, one sigma.-   4. To provide a system that substantially reduces the incidence of    single vehicle accidents caused by the vehicle inappropriately    leaving the roadway at high speed.-   5. To provide a system which does not require modification to a    roadway which permits high speed controlled travel of vehicles on    the roadway thereby increasing the vehicle flow rate on congested    roads.-   6. To provide a collision avoidance system comprising a sensing    system responsive to the presence of at least one other vehicle in    the vicinity of the equipped vehicle and means to determine the    location of the other vehicle relative to the lane boundaries of the    roadway and thereby determine if the other vehicle has strayed from    its proper position on the highway thereby increasing the risk of a    collision, and taking appropriate action to reduce that risk.-   7. To provide a means whereby vehicles near each other can    communicate their position and/or their velocity to each other and    thereby reduce the risk of a collision.-   8. To provide a means for accurate maps of a roadway to be    transmitted to a vehicle on the roadway.-   9. To provide a means for weather, road condition and/or similar    information can be communicated to a vehicle traveling on a roadway    plus means within the vehicle for using that information to reduce    the risk of an accident.-   10. To provide a means and apparatus for a vehicle to precisely know    its location at certain positions on a road by passing through or    over an infrastructure based local subsystem thereby permitting the    vehicle electronic systems to self correct for the satellite errors    making the vehicle for a brief time a DGPS station and facilitate    carrier phase DGPS for increased location accuracy. Such a subsystem    may be a PPS including one based on the signature of the    environment.-   11. To utilize government operated navigation aid systems such as    the WAAS and LAAS as well as other available or to become available    systems to achieve sub-meter vehicle location accuracies.-   12. To utilize the OpenGIS™ map database structure so as to promote    open systems for accurate maps for the RtZF™ system.-   13. To eliminate intersection collisions caused by a driver running    a red light or stop sign.-   14. To eliminate intersection collisions caused by a driver    executing a turn into oncoming traffic.-   15. To provide a method of controlling the speed of a vehicle based    on map information or information transmitted to the vehicle from    the infrastructure. Such speed control may be based on information    as to the normal legal speed limit or a variable speed limit set by    weather or other conditions.

Other improvements will now be obvious to those skilled in the art. Theabove features are meant to be illustrative and not definitive.

The preferred embodiments of the inventions are shown in the drawingsand described in the detailed description below. Unless specificallynoted, it is applicant's intention that the words and phrases in thespecification and claims be given the ordinary and accustomed meaning tothose of ordinary skill in the applicable art(s). If applicant intendsany other meaning, he will specifically state he is applying a specialmeaning to a word or phrase.

Likewise, applicant's use of the word “function” in the detaileddescription is not intended to indicate that he seeks to invoke thespecial provisions of 35 U.S.C. §112, ¶6 to define his invention. To thecontrary, if applicant wishes to invoke the provision of 35 U.S.C. §112,¶6, to define his invention, he will specifically set forth in theclaims the phrases “means for” or “step for” and a function, withoutalso reciting in that phrase any structure, material or act in supportof the function. Moreover, even if applicant invokes the provisions of35 U.S.C. §112, ¶6, to define his invention, it is applicant's intentionthat his inventions not be limited to the specific structure, materialor acts that are described in preferred embodiments. Rather, ifapplicant claims his invention by specifically invoking the provisionsof 35 U.S.C. §112, ¶6, it is nonetheless his intention to cover andinclude any and all structures, materials or acts that perform theclaimed function, along with any and all known or later developedequivalent structures, materials or acts for performing the claimedfunction.

For example, the present inventions make use of GPS satellite locationtechnology, including the use of MIR or RFID triads or radar andreflectors, to derive kinematic vehicle location and motion trajectoryparameters for use in a vehicle collision avoidance system and method.The inventions described herein are not to be limited to the specificGPS devices or PPS devices disclosed in the preferred embodiments, butrather, are intended to be used with any and all such applicablesatellite and infrastructure location devices, systems and methods, aslong as such devices, systems and methods generate input signals thatcan be analyzed by a computer to accurately quantify vehicle locationand kinematic motion parameters in real time. Thus, the GPS and PPSdevices and methods shown and referenced generally throughout thisdisclosure, unless specifically noted, are intended to represent any andall devices appropriate to determine such location and kinematic motionparameters.

Likewise, for example, the present inventions generate surveillanceimage information for analysis by scanning using any applicable image orvideo scanning system or method. The inventions described herein are notto be limited to the specific scanning or imaging devices or to aparticular electromagnetic frequency or frequency range or part of theelectromagnetic spectrum disclosed in the preferred embodiments, butrather, are intended to be used with any and all applicable electronicscanning devices, as long as the device can generate an output signalthat can be analyzed by a computer to detect and categorize objects.Thus, the scanners or image acquisition devices are shown and referencedgenerally throughout this disclosure, and unless specifically noted, areintended to represent any and all devices appropriate to scan or image agiven area. Accordingly, the words “scan” or “image” as used in thisspecification should be interpreted broadly and generically.

Further, there are disclosed several processors or controllers, thatperform various control operations. The specific form of processor isnot important to the invention. In its preferred form, applicant dividesthe computing and analysis operations into several cooperating computersor microprocessors. However, with appropriate programming well known tothose of ordinary skill in the art, the inventions can be implementedusing a single, high power computer. Thus, it is not applicant'sintention to limit his invention to any particular form or location ofprocessor or computer. For example, it is contemplated that in somecases the processor may reside on a network connected to the vehiclesuch as one connected to the Internet.

Further examples exist throughout the disclosure, and it is notapplicant's intention to exclude from the scope of his invention the useof structures, materials, or acts that are not expressly identified inthe specification, but nonetheless are capable of performing a claimedfunction.

The above and other objects are achieved in the present invention whichprovides motor vehicle collision avoidance, warning and control systemsand methods using GPS satellite location systems augmented with PrecisePositioning Systems to provide centimeter location accuracy, and toderive vehicle attitude and position coordinates and vehicle kinematictracking information. GPS location and computing systems beingintegrated with vehicle video scanning, radar, laser radar, terahertzradar and onboard speedometer and/or accelerometers and gyroscopes toprovide accurate vehicle location information together with informationconcerning hazards and/or objects that represent impending collisionsituations for each vehicle. Advanced image processing techniques areused to quantify video information signals and to derive vehicle warningand control signals based upon detected hazards.

Outputs from multiple sensors as described above are used in onboardvehicle neural network and neural-fuzzy system computing algorithms toderive optimum vehicle warning and control signals designed to avoidvehicle collisions with other vehicles or with other objects or hazardsthat may be present on given roadways. In a preferred embodiment, neuralfuzzy control algorithms are used to develop coordinated braking,acceleration and steering control signals to control individualvehicles, or the individual wheels of such vehicles, in an optimalmanner to avoid or minimize the effects of potential collisions. Video,radar, laser radar, terahertz radar and GPS position and trajectoryinformation are made available to each individual vehicle describing themovement of that vehicle and other vehicles in the immediate vicinity ofthat vehicle.

In addition, hazards or other obstacles that may represent a potentialdanger to a given vehicle are also included in the neural fuzzycalculations. Objects, obstacles and/or other vehicles located anywhereto the front, rear or sides of a given vehicle are considered in thefuzzy logic control algorithms in the derivation of optimal control andwarning signals.

The above and other objects and advantages of the present invention areachieved by the preferred embodiments that are summarized and describedin detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The various hardware and software elements used to carry out theinvention described herein are illustrated in the form of systemdiagrams, block diagrams, flow charts, and depictions of neural networkalgorithms and structures. The preferred embodiment is illustrated inthe following figures:

FIG. 1 illustrates the GPS satellite system with the 24 satellitesrevolving around the earth.

FIG. 2 illustrates four GPS satellites transmitting position informationto a vehicle and to a base station which in turn transmits thedifferential correction signal to the vehicle.

FIG. 3 illustrates a WADGPS system with four GPS satellites transmittingposition information to a vehicle and to a base station which in turntransmits the differential correction signal to the vehicle.

FIG. 4 is a logic diagram showing the combination of the GPS system andan inertial navigation system.

FIG. 5 is a block diagram of the overall vehicle accident avoidance,warning, and control system and method of the present inventionillustrating system sensors, radio transceivers, computers, displays,input/output devices and other key elements.

FIG. 5A is a block diagram of a representative accident avoidance,warning and control system.

FIG. 6 is a block diagram of an image analysis computer of the type thatcan be used in the accident avoidance system and method of thisinvention.

FIG. 7 illustrates a vehicle traveling on a roadway in a definedcorridor.

FIG. 8 illustrated two adjacent vehicles traveling on a roadway andcommunicating with each other.

FIG. 9 is a schematic diagram illustrating a neural network of the typeuseful in the image analysis computer of FIG. 5.

FIG. 10 is a schematic diagram illustrating the structure of a nodeprocessing element in the neural network of FIG. 9.

FIG. 11 illustrates the use of a Precise Positioning System employingthree micropower impulse radar transmitters, two or three radarreflectors or three RFID tags in a configuration to allow a vehicle toaccurately determine its position.

FIG. 12 a is a flow chart of the method in accordance with the inventionfor preventing run off the road accidents.

FIG. 12 b is a flow chart of the method in accordance with the inventionfor preventing center (yellow) line crossing accidents.

FIG. 12 c is a flow chart of the method in accordance with the inventionfor preventing stoplight running accidents.

FIG. 13 illustrates an intersection with stop signs on the lesser roadwhere there is a potential for a front to side impact and a rear endimpact.

FIG. 14 illustrates a blind intersection with stoplights where there isa potential for a front side to front side impact.

FIG. 15 illustrates an intersection where there is a potential for afront-to-front impact as a vehicle turns into oncoming traffic.

FIG. 16A is a side view of a vehicle equipped with a road-mappingarrangement in accordance with the invention.

FIG. 16B is a front perspective view of a vehicle equipped with theroad-mapping arrangement in accordance with the invention.

FIG. 17 is a schematic perspective view of a data acquisition module inaccordance with the invention.

FIG. 17A is a schematic view of the data acquisition module inaccordance with the invention.

FIG. 18 shows the view of a road from the video cameras in both of thedata acquisition modules.

FIG. 19 shows a variety of roads and vehicles operating on those roadsthat are in communication with a vehicle that is passing through aPrecise Positioning Station.

FIG. 20 is a schematic of the manner in which communications between avehicle and a transmitter are conducted according to some embodiments ofthe invention.

FIGS. 21A and 21B illustrate a preferred embodiment of a laser radarsystem mounted at the four corners of a vehicle above the headlights andtail lights.

FIGS. 22A and 22B illustrate the system of FIGS. 21A and 21B forvehicles on a roadway.

FIGS. 23A and 23B illustrate an alternative mounting location for laserradar units.

FIG. 24 is a schematic illustration of a typical laser radar deviceshowing the scanning or pointing system with simplified optics.

FIG. 25 is a schematic showing a method for avoiding collisions inaccordance with the invention.

DETAILED DISCUSSION OF THE PREFERRED EMBODIMENTS

1. Vehicle Collision Warning and Control

According to U.S. Pat. No. 5,506,584, the stated goals of the US DOTIVHS system are:

-   -   improving the safety of surface transportation    -   increasing the capacity and operational efficiency of the        surface transportation system    -   enhancing personal mobility and the convenience and comfort of        the surface transportation system    -   reducing the environmental and energy impacts of the surface        transportation system

The RtZF™ system in accordance with the present invention satisfies allof these goals at a small fraction of the cost of prior art systems. Thesafety benefits have been discussed above. The capacity increase isachieved by confining vehicles to corridors where they are thenpermitted to travel at higher speeds. This can be achieved immediatelywhere carrier phase DGPS is available or with the implementation of thehighway-located precise location systems as shown in FIG. 11. Animprovement is to add the capability for the speed of the vehicles to beset by the highway or highway control system. This is a simpleadditional few bytes of information that can be transmitted along withthe road edge location map, thus, at very little initial cost. Toaccount for the tolerances in vehicle speed control systems, thescanning laser radar, or other technology system, which monitors for thepresence of vehicles without RtZF™ is also usable as an adaptive cruisecontrol system. Thus, if a faster moving vehicle approaches a slowermoving vehicle, it will automatically slow down to keep a safeseparation distance from the leading, slower moving vehicle. Althoughthe system is not planned for platooning, that will be the automaticresult in some cases. The maximum packing of vehicles is automaticallyobtained and thus the maximum vehicle flow rate is also achieved with avery simple system.

For the Intelligent Highway System (ITS) application, some provision isrequired to prevent unequipped vehicles from entering the restrictedlanes. In most cases, a barrier will be required since if an errantvehicle did enter the controlled lane, a serious accident could result.Vehicles would be checked while traveling down the road or at atollbooth, or similar station, that the RtZF™ system was in operationwithout faults and with the latest updated map for the region. Onlythose vehicles with the RtZF™ system in good working order would bepermitted to enter. The speed on the restricted lanes would be setaccording to the weather conditions and fed to the vehicle informationsystem automatically, as discussed above. Automatic tolling based on thetime of day or percentage of highway lane capacity in use can also beeasily implemented.

For ITS use, there needs to be a provision whereby a driver can signalan emergency, for example, by putting on the hazard lights. This wouldpermit the vehicle to leave the roadway and enter the shoulder when thevehicle velocity is below a certain level. Once the driver provides sucha signal, the roadway information system, or the network ofvehicle-based control systems, would then reduce the speed of allvehicles in the vicinity until the emergency has passed. This roadwayinformation system need not be actually associated with the particularroadway and also need not require any roadway infrastructure. It is aterm used here to represent the collective system as operated by thenetwork of nearby vehicles and the inter-vehicle communication system.Eventually, the occurrence of such emergency situations will beeliminated by vehicle-based failure prediction systems such as describedin U.S. Pat. No. 5,809,437.

Emergency situations will develop on intelligent highways. It isdifficult to access the frequency or the results of such emergencies.The industry has learned from airbags that if a system is developedwhich saves many lives but causes a few deaths, the deaths will not betolerated. The ITS system, therefore, must operate with a very highreliability, that is approaching “zero fatalities”™. Since the brains ofthe system will reside in each vehicle, which is under the control ofindividual owners, there will be malfunctions and the system must beable to adapt without causing accidents. An alternative is for thebrains to reside on the network providing that the network connection isreliable.

The spacing of the vehicles is the first line of defense. Secondly, eachvehicle with a RtZF™ system has the ability to automatically communicateto all adjacent vehicles and thus immediately issue a warning when anemergency event is occurring. Finally, with the addition of a totalvehicle diagnostic system, such as disclosed in U.S. Pat. No. 5,809,437(Breed), “On Board Vehicle Diagnostic System”, potential emergencies canbe anticipated and thus eliminated with high reliability.

Although the application for ITS envisions a special highway lane andhigh speed travel, the potential exists in the invention to provide alower measure of automatic guidance where the operator can turn controlof the vehicle over to the RtZF™ system for as long as theinfrastructure is available. In this case, the vehicle would operate innormal lanes but would retain its position in the lane and avoidcollisions until a decision requiring operator assistance is required.At that time, the operator would be notified and if he or she did notassume control of the vehicle, an orderly stopping of the vehicle, e.g.,on the side of the road, would occur.

For all cases where vehicle steering control is assumed by the RtZF™system, an algorithm for controlling the steering should be developedusing neural networks or neural fuzzy systems. This is especially truefor the emergency cases discussed herein where it is well known thatoperators frequently take the wrong actions and at the least, they areslow to react. Algorithms developed by other non-pattern recognitiontechniques do not, in general, have the requisite generality orcomplexity and are also likely to make the wrong decisions (although theuse of such systems is not precluded in the invention). When thethrottle and breaking functions are also handled by the system, analgorithm based on neural networks or neural fuzzy systems is even moreimportant.

For the ITS, the driver will enter his or her destination so that thevehicle knows ahead of time where to exit. Alternately, if the driverwishes to exit, he merely turns on his turn signal, which tells thesystem and other vehicles that he or she is about to exit the controlledlane.

Neural networks have been mentioned above and since they can play animportant role in various aspects of the invention, a brief discussionis now presented here. FIG. 9 is a schematic diagram illustrating aneural network of the type useful in image analysis. Data representingfeatures from the images from the CMOS cameras 60 are input to theneural network circuit 63, and the neural network circuit 63 is thentrained on this data (see FIG. 6). More specifically, the neural networkcircuit 63 adds up the feature data from the CMOS cameras 60 with eachdata point multiplied by an associated weight according to theconventional neural network process to determine the correlationfunction.

In this embodiment, 141 data points are appropriately interconnected at25 connecting points of layer 1, and each data point is mutuallycorrelated through the neural network training and weight determinationprocess. In some implementations, each of the connecting points of thelayer 1 has an appropriate threshold value, and if the sum of measureddata exceeds the threshold value, each of the connecting points willoutput a signal to the connecting points of layer 2. In other cases, anoutput value or signal will always be outputted to layer 2 withoutthresholding.

The connecting points of the layer 2 comprises 20 points, and the 25connecting points of the layer 1 are appropriately interconnected as theconnecting points of the layer 2. Similarly, each data value is mutuallycorrelated through the training process and weight determination asdescribed above and in the above referenced neural network texts. Eachof the 20 connecting points of the layer 2 can also have an appropriatethreshold value, if thresholding is used, and if the sum of measureddata exceeds the threshold value, each of the connecting points willoutput a signal to the connecting points of layer 3.

The connecting points of the layer 3 comprises 3 points in this example,and the connecting points of the layer 2 are interconnected at theconnecting points of the layer 3 so that each data is mutuallycorrelated as described above.

The value of each connecting point is determined by multiplying weightcoefficients and summing up the results in sequence, and theaforementioned training process is to determine a weight coefficient Wjso that the value (ai) is a previously determined output.ai=ΣWj·Xj(j=1 to N)+W ₀

-   -   wherein Wj is the weight coefficient,        -   Xj is the data        -   N is the number of samples and        -   W₀ is bias weight associated with each node.

Based on this result of the training, the neural network circuit 63generates the weights and the bias weights for the coefficients of thecorrelation function or the algorithm.

At the time the neural network circuit 63 has learned from a suitablenumber of patterns of the training data, the result of the training istested by the test data. In the case where the rate of correct answersof the object identification unit based on this test data isunsatisfactory, the neural network circuit 63 is further trained and thetest is repeated. Typically, about 200,000 feature patterns are used totrain the neural network 63 and determine all of the weights. A similarnumber is then used for the validation of the developed network. In thissimple example chosen, only three outputs are illustrated. These canrepresent another vehicle, a truck and a pole or tree. This might besuitable for an early blind spot detector design. The number of outputsdepends on the number of classes of objects that are desired. However,too many outputs can result in an overly complex neural network and thenother techniques such as modular neural networks can be used to simplifythe process. When a human looks at a tree, for example, he or she mightthink “what kind of tree is that?” but not “what kind of tiger is that”.The human mind operates with modular or combination neural networkswhere the object to be identified is first determined to belong to ageneral class and then to a subclass etc. Object recognition neuralnetworks can frequently make use of this principle with a significantsimplification resulting.

In the above example, the image was first subjected to a featureextraction process and the feature data was input to the neural network.In other cases, especially as processing power continues to advance, theentire image is input to the neural network for processing. Thisgenerally requires a larger neural network. Alternate approaches usedata representing the difference between two frames and the input datato the neural network. This is especially useful when a moving object ofinterest is in an image containing stationary scenery that is of nointerest. This technique can be used even when everything is moving byusing the relative velocity as a filter to remove unwanted pixel data.Any variations are possible and will now be obvious to those skilled inthe art. Alternately, this image can be filtered based on range, whichwill also significantly reduce the number of pixels to be analyzed.

In another implementation, the scenes are differenced based onillumination. If infrared illumination is used, for example, theillumination can be turned on and off and images taken and thendifferenced. If the illumination is known only to illuminate an objectof interest then such an object can be extracted from the background bythis technique. A particularly useful method is to turn the illuminationon and off for alternate scan lines in the image. Adjacent scan linescan then be differenced and the resulting image sent to the neuralnetwork system for identification.

The neural network can be implemented as an algorithm on ageneral-purpose microprocessor or on a dedicated parallel processingDSP, neural network ASIC or other dedicated parallel or serialprocessor. The processing speed is generally considerably faster whenparallel processors are used and this can also permit the input of theentire image for analysis rather than using feature data. A combinationof feature and pixel data can also be used.

Neural networks have certain known potential problem areas that variousresearchers have attempted to eliminate. For example, if datarepresenting an object that is totally different from those objectspresent in the training data is input to the neural network, anunexpected result can occur which, in some cases, can cause a systemfailure. To solve this and other neural network problems, researchershave resorted to adding in some other computational intelligenceprinciples such as fuzzy logic resulting in a neural-fuzzy system, forexample. As the RtZF™ system evolves, such refinements will beimplemented to improve the accuracy of the system. Thus, although pureneural networks are currently being applied to the problem, hybridneural networks such as modular, combination, ensemble and fuzzy neuralnetworks will undoubtedly evolve.

A typical neural network processing element known to those skilled inthe art is shown in FIG. 10 where input vectors, (X1, X2 . . . Xn) areconnected via weighing elements 120 (W1, W2 . . . Wn) to a summing node130. The output of node 130 is passed through a nonlinear processingelement 140, typically a sigmoid function, to produce an output signal,Y. Offset or bias inputs 125 can be added to the inputs throughweighting circuit 128. The output signal from summing node 130 is passedthrough the nonlinear element 140 which has the effect of compressing orlimiting the magnitude of the output Y.

Neural networks used in the accident avoidance system of this inventionare trained to recognize roadway hazards including automobiles, trucks,animals and pedestrians. Training involves providing known inputs to thenetwork resulting in desired output responses. The weights areautomatically adjusted based on error signal measurements until thedesired outputs are generated. Various learning algorithms may beapplied with the back propagation algorithm with the Delta Bar rule as aparticularly successful method.

2. Accurate Navigation

2.1 GPS

FIG. 1 shows the current GPS satellite system associated with the earthand including 24 satellites 2, each satellite revolving in a specificorbital path 4 around the earth. By means of such a GPS satellitesystem, the position of any object can be determined with varyingdegrees of precision as discussed in detail herein. A similar systemwill appear when the European Galileo system is launched perhapsdoubling the number of satellites.

2.2 DGPS, WAAS, LAAS and Pseudolites

FIG. 2 shows an arrangement of four satellites 2 designated SV₁, SV₂,SV₃ and SV₄ of the GPS satellite system shown in FIG. 1 transmittingposition information to receiver means of a base station 20, such as anantenna 22, which in turn transmits a differential correction signal viatransmitter means associated with that base station, such as a secondantenna 16, to a vehicle 18.

Additional details relating to FIGS. 1 and 2 can be found in U.S. Pat.No. 5,606,506 to Kyrtsos, which is incorporated by reference herein.

FIG. 3 shows an arrangement of four satellites 2 designated SV₁, SV₂,SV₃ and SV₄ of the GPS satellite system as in FIG. 2 transmittingposition information to receivers of base stations 20 and 21, such as anantenna 22, which in turn transmit a differential correction signal viatransmitter means associated with that base stations, such as a secondantenna 16, to a geocentric or low earth orbiting (LEO) satellite 30which in turn transmits the differential correction signals to vehicle18. In this case, one or more of the base stations 20,21 receives andperforms a mathematical analysis on all of the signals received from anumber of base stations that cover the area under consideration andforms a mathematical model of the errors in the GPS signals over theentire area. For the CONUS, for example, a group of 13 base stations areoperated by OmniStar that are distributed around the country. Byconsidering data from the entire group of such stations, the errors inthe GPS signals for the entire area can be estimated resulting in aposition accuracy of about 6–10 cm over the entire area. The correctionsare then uploaded to the geocentric or low earth orbiting satellite 30for retransmission to vehicles on the roadways. In this way, suchvehicles are able to determine their absolute position to within about6–10 centimeters. This is known as Wide Area Deferential GPS or WADGPS.

It is important to note that future GPS and Galileo satellite systemsplan for the transmission of multiple frequencies for civilian use. Likea lens, the ionosphere diffracts different frequencies by differentamounts and thus the time of arrival of a particular frequency willdepend on the value of that frequency. This fact can be used todetermine the amount that each frequency is diffracted and thus thedelay or error introduced by the ionosphere. Thus with more than onefrequency being emitted by a particular satellite, the equivalent of theDGPS corrections can be determined be each receiver and there in nolonger a need for DGPS, WADGPS, WAAS, LAAS and similar systems.

The WAAS system is another example of WADGPS for use with airplanes. TheU.S. Government estimates that the accuracy of the WAAS system is about1 meter in three dimensions. Since the largest error is in the verticaldirection, the horizontal error is much less.

2.3 Carrier Phase Measurements

If a receiver can receive signals by two paths from a satellite it canmeasure the phase difference between the two paths and, provided thatthere are not any extra cycles in one of the paths, the path differencecan be determined to less than one centimeter. The fact that there maybe an integer number of extra cycles in one path and not in the other iswhat is called the integer ambiguity problem and a great deal ofattention has been paid in the literature to resolving this ambiguity.Using the Precise Positioning System (PPS) described in detail belowwhere a vehicle becomes its own DGPS system, the carrier phase ambiguityproblem also disappears since the number of additional cycles can bedetermined as the vehicle travels away from the PPS. In other words,there are no extra cycles when the vehicle is at the PPS and as it movesaway, it will still know the state of the cycles at the PPS and can thencalculate the increase or decrease in the cycles at the host vehicle asit moves relatively away from or closer to the transmitting satellite.There is no ambiguity when the vehicle is at the PPS station and that ismaintained as long as the lock on a satellite is not lost for more thana few minutes providing that there is an accurate clock within thevehicle.

There are other sources of information that can be added to increase theaccuracy of position determination. The use of GPS with four satellitesprovides the three-dimensional location of the vehicle plus time. Of thedimensions, the vertical position is the least accurately known, yet, ifthe vehicle knows where it is on the roadway, the vertical dimension isnot only the least important but it is also already accurately knownfrom the roadmap information plus the inertial guidance system.

2.4 Inertial Navigation System

In the system of the inventions herein, the vehicle will generally havean inertial measurement unit, inertial reference unit or an inertialnavigation system which for the purposes herein will be treated asidentical. Such a device typically has three accelerometers and threegyroscopes that are held together in a single housing. Typically, these6 devices are MEMS devices and inherently are very inexpensive. Somecompanies then proceed to carefully test each component to determine therepeatable effects that various environmental factors and aging has onthe performance of each device and then associates with each device, acalibration or constitute equation that translates the readings of thedevice to actual values based on the environmental variable values andtime. This process adds significantly to the cost and in fact may be thedominant cost. The problem is that age, for example, may affect a devicedifferently based on how the aging takes place, at high or lowtemperatures, for example. Also shock or some other unexpected event canchange the properties of a device. In the present invention, on theother hand, this complicated and expensive calibration process is notperformed and thus a calibration equation is not frozen into the device.Since the IMU will be part of a vehicle system and that system willperiodically, either from the GPS-DGPS type system or from the PPS, knowits exact location, that fact will be used to derive a calibrationequation for each device and since other information such as temperatureetc. will also be known that parameter can also be part of the equation.The equation can thus be a changing part of the system thatautomatically adjusts to actual experience of the vehicle in the field.Thus, not only is the IMU more accurate than the prior art but it isconsiderably less expensive. One method for handling this change andrecalculation of the calibration equations would be to use an adaptiveneural network that has a forgetting function. Properly designed, thisnetwork can allow the calibration equations to adjust and slowly changeover time always providing the most accurate values regardless of howthe devices are changing in their sensitivity to temperature, forexample.

The fact that the IMU resident devices are continuously calibrated usingexternal measurements renders the IMU an extremely accurate devicecomparable with military grade IMUs costing thousands of dollars. TheIMU is far more accurate, for example, than the crash sensor or chassiscontrol accelerometers and gyroscopes that are currently being deployedon a vehicle. Thus, when mounting location considerations permit, theIMU can take over the functions currently performed by these otherdevices. This will not only increase the accuracy of these otherfunctions but reduce the total cost by eliminating the need forredundant parts and permitting economies in the electronic circuits andprocessors to be realized. The airbag SDM can now be housed with theIMU, for example, and similarly for the chassis control electronics. Ifthe IMU has the full complement of three gyros and three accelerometers,then this additional information can be used to substantially improvethe crash sensing algorithms or the chassis control algorithms. Thesensing and predicting or a rollover event, for example, and thesubsequent control of the throttle, brakes and steering systems as wellas the timely deployment of the side and curtain airbags. Thus, the useof the IMU for these functions, particularly for the rolloverprediction, mitigation and restraint deployment functions, are a keyteaching of this invention.

As discussed below, many sensors can be used to correct the errors inthe IMU in addition to the GPS and PPS based systems. A gravity metercan determine the direction of vertically down and can especially beused when the vehicle is not moving. A magnetic flux gate compass and/ordeclinometer values can be included in the map database and compared bythe host vehicle as it passes mapped areas. Doppler radar or othervelocity measurements from the exterior vehicle monitoring system canprovide valuable velocity information. Vision systems can be used tocorrect for position if such data is stored on the map database. If, forexample a stored picture shows a signpost at a particular location thatcan be viewed by a resident vision system, then this can also be usefulinformation for correcting errors in the IMU.

In many cases, especially before the system implementation becomesmature and the complete infrastructure is in place, there will be timeswhen a particular vehicle system is not operational. This could be dueto obstructions hiding a clear view of a sufficient number of GPSsatellites, such as when a vehicle enters a tunnel. It could also be dueto a lack of road boundary information, due to construction or the factthat the road has not been surveyed and the information recorded andmade available to the vehicle, or a variety of other causes. It iscontemplated, therefore, that each equipped vehicle will contain awarning light or other system that warns the driver or the vehiclecontrol system when the system is not operational. If this occurs on oneof the specially designated highway lanes, the vehicle speed will bereduced until the system again becomes operational.

When the system is non-operational for a short distance, the vehiclewill still accurately know its position if there is, in addition, one ormore laser gyroscopes, micromachined angular rate sensors or equivalent,and one or more accelerometers that together are referred to as anInertial Navigation System (INS, IMU) or inertial measurement unit(IMU). Generally, such an INS will have three gyroscopes and threeaccelerometers and frequently there may be more than one IMU in avehicle. Although current versions of the IMU use MEMS devices, progressis being made on fiber optic-based gyroscopes. Thus, the presentinvention is not limited to MEMS devices but will make use of the bestcost effective devices that are available at a particular time.

As more sensors which are capable of providing information on thevehicle position, velocity and acceleration are added onto the vehicle,the system can become sufficiently complicated as to require a Kalmanfilter, neural network, or neural-fuzzy, system to permit the optimumusage of the available information. This becomes even more importantwhen information from outside the vehicle other than the GPS relatedsystems becomes more available. For example, a vehicle may be able tocommunicate with other vehicles that have similar systems and learntheir estimated location. If the vehicle can independently measure theposition of the other vehicle, for example through the use of thescanning laser radar system described below, the differential GPSreadings as discussed above, and thereby determine the relative positionof the two or more vehicles, a further improvement of the position canbe determined for all such vehicles. Adding all such additionalinformation into the system would probably require a computationalmethod such as Kalman filters, neural networks or a combination thereofand perhaps a fuzzy logic system.

One way to imagine the system operation is to consider each car androadway edge to behave as if it had a surrounding “force field” thatwould prevent it from crashing into another vehicle or an obstacle alongthe roadway. A vehicle operator would be prevented from causing his orher vehicle to leave its assigned corridor. This is accomplished with acontrol system that controls the steering, acceleration and perhaps thevehicle brakes based on its knowledge of the location of the vehicle,highway boundaries and other nearby vehicles. In a preferredimplementation, the location of the vehicle is determined by first usingthe GPS L1 signal to determine its location within approximately 100meters. Then, using DGPS and corrections which are broadcast, whether byFM or downloaded from geo-synchronous (GEO) or Low Earth Orbiting (LEO)satellites or obtained from another vehicle or road-based transmitters,to determine its location within less than about 10 centimeters.Finally, the use of a PPS, discussed below, periodically permits thevehicle to determine its exact location and thereby determine the GPScorrections, eliminate the carrier cycle ambiguity and correct theerrors in the INS or IMU system. If this is still not sufficient, thenthe phase of the carrier frequency provides the required locationinformation to less than a few centimeters. Dead reckoning, usingvehicle speed, steering angle and tire rotation information and inertialguidance, can be used to fill in the gaps. Where satellites are out ofview, pseudolites, or other systems, can be placed along the highway. Apulsed scanning infrared laser or terahertz radar system, or anequivalent system, can be used for obstacle detection. Communication toother vehicles is by short distance radio or by spread spectrum timedomain pulse radar or terahertz.

3. Maps and Mapping

3.1 Maps

All information regarding the road, both temporary and permanent, shouldbe part of the map database, including speed limits, presence of guardrails, width of each lane, width of the highway, width of the shoulder,character of the land beyond the roadway, existence of poles or treesand other roadside objects, exactly where the precise position locationapparatus is located, etc. The speed limit associated with particularlocations on the maps should be coded in such a way that the speed limitcan depend upon the time of day and the weather conditions. In otherwords, the speed limit is a variable that will change from time to timedepending on conditions. It is contemplated that there will be a displayfor various map information which will always be in view for thepassenger and for the driver at least when the vehicle is operatingunder automatic control. Additional user information can thus also bedisplayed such as traffic conditions, weather conditions,advertisements, locations of restaurants and gas stations, etc.

A map showing the location of road and lane boundaries can be easilygenerated using a specially equipped survey vehicle that has the mostaccurate position measurement system available. In some cases, it mightbe necessary to set up one or more temporary local DGPS base stations inorder to permit the survey vehicle to know its position within a fewcentimeters. The vehicle would drive down the roadway while operators,using specially designed equipment, sight the road edges and lanes. Thiswould probably best be done with laser pointers and cameras. Transducersassociated with the pointing apparatus record the angle of the apparatusand then by triangulation determine the distance of the road edge orlane marking from the survey vehicle. Since the vehicle's position wouldbe accurately known, the boundaries and lane markings can be accuratelydetermined. It is anticipated that the mapping activity would take placecontinuously such that all roads in a particular state would beperiodically remapped in order to record any changes which were missedby other monitoring systems and to improve the reliability of the mapsby minimizing the chance for human error. Any roadway changes that werediscovered would trigger an investigation as to why they were notrecorded earlier thus adding feedback to the mapping part of theprocess.

The above-described method depends on human skill and attention and thusis likely to result in many errors. A preferred approach is to carefullyphotograph the edge of the road and use the laser pointers to determinethe location of the road lines relative to the pointers and to determinethe slope of the roadway through triangulation. In this case, severallaser pointers would be used emanating from above, below and to thesides of the camera. The reduction of the data is then done later usingequipment that can automatically pick out the lane markings and thereflected spots from the laser pointers. One aid to the mapping processis to place chemicals in the line paint that could be identified by thecomputer software when the camera output is digitized. This may requirethe illumination of the area being photographed by an infrared orultraviolet light, for example.

In some cases where the roadway is straight, the survey vehicle couldtravel at moderate speed while obtaining the boundary and lane locationinformation. In other cases, where the road in turning rapidly, morereadings would be required per mile and the survey vehicle would need totravel more slowly. In any case, the required road information can beacquired semi-automatically with the survey vehicle traveling at amoderate speed. Thus, the mapping of a particular road would not requiresignificant time or resources. It is contemplated that a few such surveyvehicles could map all of the interstate highways in the U.S. in lessthan one year.

The mapping effort could be supplemented and cross-checked though theuse of accurate detailed digital photogrammetic systems which, forexample, can determine the road altitude with an accuracy to <50 cm.Efforts are underway to map the earth with 1-meter accuracy. Thegenerated maps could be used to check the accuracy and for missinginfrastructure or other roadside installations of the road-determinedmaps.

Another improvement that can be added to the system based on the maps isto use a heads-up display for in-vehicle signage. As the vehicle travelsdown the road, the contents of roadside signs can be displayed on aheads up display, providing such a display is available in the vehicle,or on a specially installed LCD display. This is based on the inclusionin the map database of the contents of all highway signs. A furtherimprovement would be to include signs having varying messages whichwould require that the message be transmitted by the sign to the vehicleand received and processed for in-vehicle display. This could be doneeither directly, by satellite, the Internet, cell phone etc.

As the roadway is being mapped, the availability of GPS satellite viewand the presence of multipath reflections from fixed structures can alsobe determined. This information can then be used to determine theadvisability of locating a local precise location system (PPS), or otherinfrastructure, at a particular spot on the roadway. Cars can also beused as probes for this process and for continuous improvement to checkthe validity of the maps and report any errors.

Multipath is the situation where more than one signal from a satellitecomes to a receiver with one of the signals resulting from a reflectionoff of a building or the ground, for example. Since multipath is afunction of geometry, the system can be designed to eliminate itseffects based on highway surveying and appropriate antenna design.Multipath from other vehicles can also be eliminated since the locationof the other vehicles will be known.

3.2 Mapping

An important part of some embodiments of the invention is the digitalmap that contains relevant information relating to the road on which thevehicle is traveling. The digital map usually includes the location ofthe edge of the road, the edge of the shoulder, the elevation andsurface shape of the road, the character of the land beyond the road,trees, poles, guard rails, signs, lane markers, speed limits, etc. asdiscussed in more detail elsewhere herein. Additionally, it can containthe signature as discussed above. This data or information is acquiredin a unique manner for use in the invention and the method for acquiringthe information and its conversion to a map database that can beaccessed by the vehicle system is part of this invention. Theacquisition of the data for the maps will now be discussed. It must beappreciated though that the method for acquiring the data and formingthe digital map can also be used in other inventions.

Local area differential GPS can be utilized to obtain maps with anaccuracy of about 2 cm (one sigma). Temporary local differentialstations are available from such companies as Trimble Navigation. Theselocal differential GPS stations can be placed at an appropriate spacingfor the road to be mapped, typically every 30 kilometers. Once a localdifferential GPS station is placed, it requires some time period such asan hour or more for the station to determine its precise location.Therefore, sufficient stations are required to cover the area that is tobe mapped within, for example, four hours. This may require as many as10 or more such differential stations for efficient mapping.

With reference to FIGS. 16A, 16B, 17 and 17A, a mapping vehicle 200 isused and obtains its location from GPS satellites and its correctionsfrom the local differential stations. Such a system is capable ofproviding the 2 cm accuracy desired for the map database. Typically, atleast two GPS receivers 226 are mounted on the mapping vehicle 200. EachGPS receiver 226 is contained within or arranged in connection with arespective data acquisition module 202, which data acquisition modules202 also contain a GPS antenna 204, an accurate inertial measurementunit (IMU) 206, a forward-looking video camera 208, a downward andoutward looking linear array camera 210 and a scanning laser radar 212.The relative position of these components in FIG. 17 is not intended tolimit the invention.

A processor including a printed circuit board 224 is coupled to the GPSreceivers 226, the IMUs 206, the video cameras 208, the linear cameras210 and the scanning laser radars 212 (see FIG. 17A). The processor 224receives information regarding the position of the vehicle from the GPSreceivers 226, and optionally the IMUs 206, and the information aboutthe road from both linear cameras 210 or from both laser radars 212, orfrom all of the linear cameras 210 and laser radars 212, and forms theroad map database. Information about the road can also come from one orboth of the video cameras 208 and be incorporated into the map database.

The map database can be of any desired structure or architecture.Preferred examples of the database structure are of the type discussedin U.S. Pat. No. 6,144,338 (Davies) and U.S. Pat. No. 6,247,019(Davies), incorporated by reference herein.

The data acquisition modules 202 are essentially identical and eachmounts to the vehicle roof on an extension assembly 214 which extendsforward of the front bumper. Extension assembly 214 includes a mountingbracket 216 from the roof of the vehicle 200 forward to each dataacquisition module 210, a mounting bracket 218 extending from the frontbumper upward to each data acquisition module 202 and a cross mountingbracket 220 extending between the data acquisition modules 202 forsupport. Since all of the data acquisition equipment is co-located, itsprecise location is accurately determined by the IMU, the mountinglocation on the vehicle and the differential GPS system.

The forward-looking video cameras 208 provide views of the road as shownin FIG. 18. These cameras 208 permit the database team to observe thegeneral environment of the road and to highlight any anomalies. Theyalso permit the reading of traffic signs and other informationaldisplays all of which can be incorporated into the database. The cameras208 can be ordinary color video cameras, high-speed video cameras, wideangle or telescopic cameras, black and white video cameras, infraredcameras, etc. or combinations thereof. In some cases, special filtersare used to accentuate certain features. For example, it has been foundthat lane markers frequently are more readily observable at particularfrequencies, such as infrared. In such cases, filters can be used infront of the camera lens or elsewhere in the optical path to blockunwanted frequencies and pass desirable frequencies. Polarizing lenseshave also been found to be useful in many cases. Normally, naturalillumination is used in the mapping process, but for some particularcases, particularly in tunnels, artificial illumination can also be usedin the form of a floodlight or spotlight that can be at any appropriatefrequency of the ultraviolet, visual and infrared portions of theelectromagnetic spectrum or across many frequencies. Laser scanners canalso be used for some particular cases when it is desirable toilluminate some part of the scene with a bright spot. In some cases, ascanning laser rangemeter can be used in conjunction with theforward-looking cameras 204 to determine the distance to particularobjects in the camera view.

The video camera system can be used by itself with appropriate softwareas is currently being done by Lamda Tech International Inc. of Waukesha,Wis., to obtain the location of salient features of a road. However,such a method to obtain accurate maps is highly labor intensive andtherefore expensive. The cameras and associated equipment in the presentinvention are therefore primarily used to supplement the linear cameraand laser radar data acquisition systems to be described now.

The mapping vehicle data acquisition modules will typically contain botha linear camera and a scanning laser radar, however, for someapplications one or the other may be omitted.

The linear camera 210 is a device that typically contains a linear CCD,CMOS or other light sensitive array of, for example, four thousandpixels. An appropriate lens provides a field of view to this camera thattypically extends from approximately the center of the vehicle out tothe horizon. This camera records a one-dimensional picture covering theentire road starting with approximately the center of the lane andextending out to the horizon. This linear array camera 210 thereforecovers slightly more than 90 degrees. Typically, this camera operatesusing natural illumination and produces effectively a continuous pictureof the road since it obtains a linear picture, or column of pixels, fortypically every one-inch of motion of the vehicle. Thus, a completetwo-dimensional panoramic view of the road traveled by the mappingvehicle is obtained. Since there are two such linear camera units, a 180degree view is obtained. This camera will typically record in full colorthus permitting the map database team to have a complete view of theroad looking perpendicular from the vehicle. The view is recorded in asubstantially vertical plane. This camera will not be able to read texton traffic signs, thus the need for the forward-looking cameras 208.Automated software can be used with the images obtained from thesecameras 208, 210 to locate the edge of the road, lane markers, thecharacter of land around and including the road and all areas that anerrant vehicle may encounter. The full color view allows thecharacterization of the land to be accomplished automatically withminimal human involvement.

The scanning laser radar 212 is typically designed to cover a 90 degreeor less scan thus permitting a rotating mirror to acquire at least foursuch scans per revolution. The scanning laser radar 212 can becoordinated or synchronized with the linear camera 210 so that eachcovers the same field of view with the exception that the camera 210typically will cover more than 90 degrees. Scanning laser radar 212 canbe designed to cover more or less than 90 degrees as desired for aparticular installation. The scanning laser radar 212 can operate in anyappropriate frequency from above ultraviolet to the terahertz.Typically, it will operate in the eye-safe portion of the infraredspectrum for safety reasons. The scanning laser radar 212 can operateeither as a pulse-modulated or a tone-modulated laser as is known in theart. If operating in the tone-modulated regime, the laser light will betypically modulated with three or more frequencies in order to eliminatedistance ambiguities. Noise or code modulated radar can also be used.

For each scan, the laser radar 212 provides the distance from thescanner to the ground for up to several thousand points in a verticalplane extending from approximately the center of the lane out to nearthe horizon. This device therefore provides precise distances andelevations to all parts of the road and its environment. The preciselocation of signs that were observed with the forward-looking cameras204, for example, can now be easily and automatically retrieved. Thescanning laser radar therefore provides the highest level of mappingautomation.

Scanning laser radars have been used extensively for mapping purposesfrom airplanes and in particular from helicopters where they have beenused to map portions of railway lines in the U.S. Use of the scanninglaser radar system for mapping roadways where the radar is mounted ontoa vehicle that is driving the road is believed to be novel to thecurrent assignee.

Ideally, all of the above-described systems are present on the mappingvehicle. Although there is considerable redundancy between the linearcamera and the scanning laser radar, the laser radar operates at oneoptical frequency and therefore does not permit the automaticcharacterization of the roadway and its environment.

As with the forward-looking cameras, it is frequently desirable to usefilters and polarizing lenses for both the scanning laser radar and thelinear camera. In particular, reflections from the sun can degrade thelaser radar system unless appropriate filters are used to block allfrequencies except frequency chosen for the laser radar.

Laser radars are frequently also referred to as ladars and lidars. Allsuch devices that permit ranging to be accomplished from a scanningsystem, including radar, are considered equivalent for the purposes ofthis invention.

3.3 Map Enhancements

Once the road edge and lane locations, and other roadway information,are transmitted to the operator, it requires very little additionalbandwidth to include other information such as the location of allbusinesses that a traveler would be interested in such as gas stations,restaurants etc. which could be done on a subscription basis. Thisconcept was partially disclosed in the '482 patent discussed above andpartially implemented in existing map databases.

Communication of information to the operator could be done eithervisually or orally as described in U.S. Pat. No. 5,177,685 or U.S.patent application Ser. No. 09/645,709 filed Aug. 14, 2000, now U.S.Pat. No. 7,126,583. Finally, the addition of a route guidance system asdescribed in other patents becomes even more feasible since the exactlocation of a destination can be determined. The system can beconfigured so that a vehicle operator could enter a phone number, forexample, or an address and the vehicle would be automatically and safelydriven to that location. Since the system knows the location of the edgeof every roadway, very little, if any, operator intervention would berequired. Even a cell phone number can be used if the cell phone has theSnapTrack GPS location system as soon to be provided by Qualcomm.

Very large may databases can now reside on a vehicle as the price ofmemory continues to drop. Soon it may be possible to store the mapdatabase of an entire country on the vehicle and to update it as changesare made. The area that is within, for example, 1000 miles from thevehicle can certainly be stored and as the vehicle travels from place toplace the remainder of the database can be updated as needed though aconnection to the Internet, for example.

4. Precise Positioning

Another important aid as part of some of the inventions disclosed hereinis to provide markers along the side(s) of roadways which can be eithervisual, passive or active transponders, reflectors, or a variety ofother technologies including objects that are indigenous to or near theroadway, which have the property that as a vehicle passes the marker itcan determine the identity of the marker and from a database it candetermine the exact location of the marker. The term “marker” is meantin the most general sense. The signature determined by a continuous scanof the environment, for example, would be a marker if it is relativelyinvariant over time such as, for example, buildings in a city.Basically, there is a lot of invariant information in the environmentsurrounding a vehicle as it travels down a road toward its destination.From time to time, a view of this invariant landscape or information maybe obstructed but it is unlikely that all of it will be during thetravel of a mile, for example. Thus, a vehicle should be able to matchthe signature sensed with the expected one in the map database andthereby obtain a precise location fix. This signature can be obtainedthrough the use of radar or laser radar technologies as reportedelsewhere herein. See in particular Section 5 below and for example,Wang Yanli, Chen Zhe, “Scene matching navigation based on multisensorimage fusion” SPIE Vol. 5286 p. 788–793, 2003.

For the case of specific markers placed on the infrastructure, if threeor more of such markers are placed along a side of the roadway, apassing vehicle can determine its exact location by triangulation. Notethat even with two such markers using radar with distance measuringcapability, the precise position of a vehicle can be determined asdiscussed below in reference to the Precise Positioning System. In fact,if the vehicle is only able to observe a single radar reflector and takemany readings as the reflector is passed, it can determine quiteaccurately its position based on the minimum distance reading that isobtained during the vehicle's motion past the reflector. Although it maybe impractical to initially place such markers along all roadways, itwould be reasonable to place them in particularly congested areas orplaces where it is known that a view of one or more of the GPSsatellites is blocked. A variation of this concept will be discussedbelow.

Although initially it is preferred to use the GPS navigationalsatellites as the base technology, the invention is not limited therebyand contemplates using all methods by which the location of the vehiclecan be accurately determined relative to the earth surface. The locationof the roadway boundaries and the location of other vehicles relative tothe earth surface are also to be determined and all relevant informationused in a control system to substantially reduce and eventuallyeliminate vehicle accidents. Only time and continued system developmentwill determine the mix of technologies that provide the most costeffective solution. All forms of information and methods ofcommunication to and between vehicles are contemplated including directcommunication with stationary and moving satellites, communication withfixed earth-based stations using infrared, optical, terahertz, radar,radio and other segments of the electromagnetic spectrum andinter-vehicle communication. Some additional examples follow:

A pseudo-GPS can be delivered from cell phone stations, in place of orin addition to satellites. In fact, the precise location of a cell phonetower need not initially be known. If it monitors the GPS satellitesover a sufficiently long time period, the location can be determined asthe calculated location statistically converges to the exact location.Thus, every cell phone tower could become an accurate DGPS base stationfor very little cost. DGPS corrections can be communicated to a vehiclevia FM radio via a sub-carrier frequency for example. An infrared orradar transmitter along the highway can transmit road boundary locationinformation. A CD-ROM or other portable mass storage can be used at thebeginning of a controlled highway to provide road boundary informationto the vehicle. Finally, it is contemplated that eventually a satellitewill broadcast periodically, perhaps every five minutes, a table ofdates covering the entire CONUS that provides the latest update date ofeach map segment. If a particular vehicle does not have the latestinformation for a particular region where it is operating, it will beable to use its cell phone or other communication system to retrievesuch road maps perhaps through the Internet or from an adjacent vehicle.Emergency information would also be handled in a similar manner so thatif a tree fell across the highway, for example, all nearby vehicleswould be notified.

One of the possible problems with the RtZF™ system described herein isoperation in certain areas of large cities such as lower Manhattan, N.Y.In such locations, unless there are a plurality of local pseudolites orprecise position location system installations or the environmentsignature system is invoked such as with adaptive associative memoriesas described above, the signals from the GPS satellites can besignificantly blocked. Also there is frequently a severe multipathproblem in cities. A solution is to use the LORAN system as a backup forsuch locations. The accuracy of LORAN can be comparable to DGPS. Use ofmultiple roadway-located Precise Positioning Systems would be a bettersolution or a complementary solution. Additionally, some locationimprovement can result from application of the SnapTrack system asdescribed in U.S. Pat. No. 5,874,914 and other patents to Krasner ofSnapTrack.

The use of geo-synchronous satellites as a substitute for earth boundbase stations in a DGPS system, with carrier phase enhancements forsub-meter accuracies, is also a likely improvement to the RtZF™ systemthat can have a significant effect in urban areas.

Another enhancement that would be possible with dedicated satellitesand/or earth bound pseudolites results from the greater control over theinformation transmitted than is available from the present GPS system.Recognizing that this system could save in excess of 40,000 lives peryear in the U.S. alone, the cost of deploying such special purposestations can easily be justified. For example, say there exists amodulated wave that is 10000 kilometers long, another one which is 1000km long etc. down to 1 cm. It would then be easy to determine theabsolute distance from one point to the other. The integer ambiguity ofRTK DGPS would be eliminated. Other types of modulation are of coursepossible to achieve the desired result of simply eliminating the carrierinteger uncertainty that is discussed in many U.S. patents and otherliterature. This is not meant to be a recommendation but to illustratethat once the decision has been made to provide information to everyvehicle that will permit it to always know its location within 10 cm,many technologies will be there to make it happen. The cost savingsresulting from eliminating fatalities and serious injuries will easilycover the cost of such technologies many times over. The provision ofadditional frequencies can also enhance the system and renderdifferential corrections unnecessary. Each frequency from a satellite isdiffracted differently by the ionosphere. The properties of theionosphere can thus be determined if multiple frequencies aretransmitted. This will partially be achieved with the launch of theEuropean Galileo GPS satellite system in combination with the U.S. GPSsystem.

It is expected, especially initially, that there will be many holes inthe DGPS or GPS and their various implementations that will leave thevehicle without an accurate means of determining its location. Theinertial navigation system described above will help in filling theseholes but its accuracy is limited to a time period significantly lessthan an hour and a distance of less than 50 miles before it needscorrecting. That may not be sufficient to cover the period between DGPSavailability. It is therefore contemplated that the RtZF™ system willalso make use of low cost systems located along the roadways that permita vehicle to accurately determine its location. One example of such asystem would be to use a group of three Micropower Impulse Radar (MIR)units such as developed by Lawrence Livermore Laboratory.

A MIR operates on very low power and periodically transmits a very shortspread spectrum radar pulse. The estimated cost of a MIR is less than$10 even in small quantities. If three such MIR transmitters, 151, 152and 153, as shown in FIG. 11, are placed along the highway and triggeredsimultaneously or with a known delay, and if a vehicle has anappropriate receiver system, the time of arrival of the pulses can bedetermined and thus the location of the vehicle relative to thetransmitters determined. The exact location of the point where all threepulses arrive simultaneously would be the point that is equidistant fromthe three transmitters 151, 152, 153 and would be located on the mapinformation. Only three devices are required since only two dimensionsneed to be determined and it is assumed that the vehicle in on the roadand thus the vertical position is known, otherwise four MIRs would berequired. Thus it would not even be necessary to have the signalscontain identification information since the vehicle would not be so faroff in its position determination system to confuse different locations.By this method, the vehicle would know exactly where it was whenever itapproached and passed such a triple-MIR installation. The MIR triad PPSor equivalent could also have a GPS receiver and thereby determine itsexact location over time as described above for cell phone towers. Afterthe location has been determined, the GPS receiver can be removed. Inthis case, the MIR triad PPS or equivalent could be placed at will andthey could transmit their exact location to the passing vehicles. Analternate method would be to leave the GPS receiver with the PPS time ofarrival of the GPS data from each satellite so that the passing vehiclesthat do not go sufficiently close to the PPS can still get an exactlocation fix. A similar system using RFID tags is discussed below.

Several such readings and position determinations can be made with oneapproach to the MIR installation, the vehicle need not wait until theyall arrive simultaneously. Also the system can be designed so that thesignals never arrive at the same time and still provide the sameaccuracy as long as there is a sufficiently accurate clock on board thevehicle. One way at looking at FIG. 11 is that transmitters 151 and 152fix the lateral position of the vehicle while transmitters 151 and 153fix the location of the vehicle longitudinally. The three transmitters151,152,153 need not be along the edges on one lane but could spanmultiple lanes and they need not be at ground level but could be placedsufficiently in the air so that passing trucks would not block the pathof the radiation from an automobile. Particularly in congested areas, itmight be desirable to code the pulses and to provide more than threetransmitters to further protect against signal blockage or multipath.

The power requirements for the MIR transmitters are sufficiently lowthat a simple photoelectric cell array can provide sufficient power formost if not all CONUS locations. With this exact location information,the vehicle can become its own DGPS station and can determine thecorrections necessary for the GPS. It can also determine the integerambiguity problem and thereby know the exact number of wave lengthsbetween the vehicle and the satellites or between the vehicle and theMIR station. These calculations can be done on vehicle if there is aconnection to a network, for example. This would be particularlyefficient as the network, once it had made the calculations for onevehicle, would have a good idea of the result for another nearby vehicleand for other vehicles passing the same spot at a different time.

MIR is one of several technologies that can be used to provide preciselocation determination. Others include the use of an RFID tag that isdesigned in cooperation with its interrogator to provide a distance tothe tag measurement. Such as RFID can be either an active device with aninternal battery or solar charger or a passive device obtaining itspower from an RF interrogation signal to charge a capacitor or aSAW-based tag operating without power. An alternate and preferred systemuses radar or other reflectors where the time of flight can be measured,as disclosed in more detail elsewhere herein.

Once a vehicle passes a Precise Positioning Station (PPS) such as theMIR triad described above, the vehicle can communicate this informationto surrounding vehicles. If the separation distance between twocommunicating vehicles can also be determined by the time-of-flight orequivalent method, then the vehicle that has just passed the triad can,in effect, become a satellite equivalent or moving pseudolite. That is,the vehicle sends (such as by reflection so as not to introduce a timedelay) its GPS data from the satellite and the receiving vehicle thengets the same message from two sources and the time difference is thetime of flight. Finally, if many vehicles are communicating theirpositions to many other vehicles along with an accuracy of positionassessment, each vehicle can use this information along with thecalculated separation distances to improve the accuracy of its positiondetermination. In this manner, as the number of such vehicles increases,the accuracy of the entire system increases until an extremely accuratepositioning system for all vehicles results. Such a system, since itcombines many sources of position information, is tolerant of thefailure of any one or even several such sources. Thus, the RtZF™ systembecomes analogous to the Internet in that it can't be shut down and thegoal of perfection is approached. Some of the problems associated withthis concept will be discussed in more detail below.

Precise Positioning was described in detail above and relates to methodsof locating a vehicle independently of GPS within sub meter accuracy.This can be done using an MIR triads; barcodes painted on the roadway;radar, laser radar or terahertz radar and infrastructure mountedreflectors; RFID markets; or through the use of matching a signatureobtained from the environment with a stored signature using, forexample, Adaptive Associative Memories (AAS) based on Cellular NeuralNetworks (CNN).

AAS is a type of neural network that is distinguished in that it can doprecise identification from poor and sparse data in contrast to ordinaryback propagation neural networks discussed elsewhere herein thatgeneralize and always give an approximate answer. Applications for AASinclude: (1) Occupant recognition (face, iris, voice print, fingerprintsetc.), and (2) Vehicle location recognition for the RtZF™ PrecisePositioning System, which is the focus here. In contrast to other PPSsystems described above, AAS permits the precise location of a vehicleon a roadway within centimeters without the use of additions to theinfrastructure. A radar, laser scanner, or terahertz radar continuouslyis projected from the vehicle toward the environment, such as theroadway to the side of the vehicle, and from the returned reflectedwaves it obtains a signature of the passing environment and compares itwith a recorded signature using ASM. This signature, for example, can bethe distance from the vehicle to the infrastructure which has beennormalized for the purpose of signature matching with some method suchas the average or some other datum. Thus it is the relative distancesignature that can be compared with a stored signature thus removing theposition of the vehicle on the roadway as a variable. When a match isfound the distance to a precise object can be determined placing thevehicle precisely on the road in both the longitudinal and lateraldimensions. As discussed above, this can make the vehicle a DGPS stationfor correction of the GPS errors but it also can be used as the primarylocation system without GPS.

Other methods can be used to precisely locate a vehicle using theinfrastructure and only one preferred method has been described herein.For example, the vertical motion signature of the vehicle can in somecases be used. This could involve determining this signature from thenatural road or a pattern of disturbances similar to a rubble strip canbe placed in the roadway and sensed by an accelerometer, microphone orother sensor. Even the signature of the magnetic or reflectiveproperties of the roadway or the environment at the side of road can becandidates with the appropriate sensors. Basically, any system thatprovides a signature indication location that is derived from theinfrastructure with appropriate sensors would qualify.

Another method, for example, is to match camera images where again anAAM can be used. Since the vehicle knows approximately where it is, therecorded signature used in the AAM will change as the vehicle moves andthus only a small amount of data need be used at a particular time. TheAAM system is fast and relatively simple. Typically twenty data pointswill be used to determine the match, for example. What follows is ageneral description of AAM Associative (context-addressable) memory isfrequently dedicated to data search and/or restoration from availablefragments. Associative retrieval requires minimal information on soughtobjects, so such a machine might be used for most complicated tasks ofdata identification for partially destroyed or corrupted images. It canbe applied to authenticity attribution, document falsificationdetection, message fragment identification in the Internet etc. as wellas signature matching with the environment for PPS.

Neural associative memory works due to multi-stability of strongfeedback systems. Common models like Hopfield networks andbi-directional associative memory provide memorization by means ofcomputation network weights. It does not corrupt previously storedimages. Unfortunately, these networks cannot be widely used because oftheir low capacity and inefficient physical memory usage. A number M ofvectors memorized does not exceed 14% of the number of neurons in thenetwork N. Since a network contains N² connections, it needs storage ofat least 25M² real weight values.

Cellular architecture can exhaustively solve the problem of physicalmemory usage. Cellular memories have band-like synaptic matrix. Thevolume (number of elements) grows linearly with respect to neuronnumber. This is why cellular neural networks (CNNs) can be useful forvery large data processing problems. Pioneering models of associativememories via CNNs were proposed in some earlier works. However, moredetailed studies showed some fundamental limitations. Indeed, it has nowbeen shown that the number of images stored is restricted by a cellsize. Hence, it does not depend on the number of neurons. A moreefficient way of redundancy reduction has also been found due toconnection selection after training. This results in the use of only asmall part of physical memory without corruption of memorized data. Thenetwork after weight selection looks like the cellular one; so bycombining cellular training algorithms and weight selection, a novelnetwork paradigm has resulted. It is an adaptive neural paradigm withgreat memorizing capacity.

At present, some breakthrough associative memories have been implementedin a software package available from the current assignee. The resultscan be applied for processing of large databases, real-time informationretrieval, PPS etc. Other applications for this technology include face,iris, fingerprint, voiceprint, character, signature, etc. recognition.

FIG. 11 shows the implementation of the invention using the PrecisePositioning System (PPS) 151, 152, 153, in which a pair of vehicles 18,26 are traveling on a roadway each in a defined corridor delineated bylines 14 and each is equipped with a system in accordance with theinvention and in particular, each is equipped with PPS receivers. Fourversions of the PPS system will now be described. This invention is notlimited to these examples but they will serve to illustrate theprincipals involved.

Vehicle 18 contains two receivers 160,161 for the micropower impulseradar (MIR) implementation of the invention. MIR transmitter devices areplaced at locations 151,152 and 153 respectively. They are linkedtogether with a control wire, not shown, or by a wireless connectionsuch that each device transmits a short radar pulse at a precise timingrelative to the others. These pulses can be sent simultaneously or at aprecise known delay. Vehicle 18 knows from its map database theexistence and location of the three MIR transmitters. The transmitters151,152 and 153 can either transmit a coded pulse or non-coded pulse. Inthe case of the coded pulse, the vehicle PPS system will be able toverify that the three transmitters 151, 512, 153 are in fact the onesthat appear on the map database. Since the vehicle will know reasonablyaccurately its location and it is unlikely that other PPS transmitterswill be nearby or within range, the coded pulse may not be necessary.Two receivers 160 and 161 are illustrated on vehicle 18. For the MIRimplementation, only a single receiver is necessary since the positionof the vehicle will be uniquely determined by the time of arrival of thethree MIR pulses. A second receiver can be used for redundancy and alsoto permit the vehicle to determine the angular position of the MIRtransmitters as a further check on the system accuracy. This can be donesince the relative time of arrival of a pulse from one of thetransmitters 151, 152, 153 can be used to determine the distance to eachtransmitter and by geometry, its angular position relative to thevehicle 18. If the pulses are coded, then the direction to the MIRtransmitters 151,152,153 will also be determinable.

The micropower impulse radar units require battery power or anotherpower mechanism to operate. Since they may be joined together with awire in order to positively control the timing of the three pulses, asingle battery can be used to power all three units. This battery canalso be coupled with a solar panel to permit maintenance free operationof the system. Since the MIR transmitters use very small amounts ofpower, they can operate for many years on a single battery.

Although the MIR systems are relatively inexpensive, on the order of tendollars each, the installation cost of the system will be significantlyhigher than the RFID and radar reflector solutions discussed next. TheMIR system is also significantly more complex than the RFID system;however, its accuracy can be checked by each vehicle that uses thesystem. Tying the MIR system to a GPS receiver and using the accurateclock on the GPS satellites as the trigger for the sending of the radarpulses can add additional advantages and complexity. This will permitvehicles passing by to additionally accurately set their clocks to be insynchronization with the GPS clocks. Since the MIR system will know itsprecise location, all errors in the GPS signals can be automaticallycorrected and in that case, the MIR system becomes a differential GPSbase station. For most implementations, this added complexity is notnecessary since the vehicle themselves will be receiving GPS signals andthey will also know precisely their location from the triad of MIRtransmitters 151, 152, 153.

A considerably simpler alternate approach to the MIR system describedabove utilizes reflective RFID tags. These tags, when interrogated by aninterrogator type of receiver 160, 161, reflect a modified RF signalwith the modification being the identification of the tag. Such tags aredescribed in many patents on RFID technology and can be produced forsubstantially less than one dollar each. The implementation of the RFIDsystem would involve the accurate placement of these tags on knownobjects on or in connection with infrastructure. These objects could bespots on the highway, posts, signs, sides of buildings, poles, orstructures that are dedicated specifically for this purpose. In fact,any structure that is rigid and unlikely to change position can be usedfor mounting RFID tags. In downtown Manhattan, building sides, streetlights, stoplights, or other existing structures are ideal locations forsuch tags. A vehicle 18 approaching a triad of such RFID tagsrepresented by 151, 152, 153 would transmit an interrogation pulse frominterrogator 160 and/or 161. The pulse would reflect off of each tagwithin range and the reflected signal would be received by the sameinterrogator(s) 160, 161 or other devices on the vehicle. Once again, asingle interrogator is sufficient. It is important to note that therange to RFID tags is severely limited unless a source of power isprovided. It is very difficult to provide enough power from RF radiationfrom the interrogator for distances much greater than a few feet. Forlonger distances, a power source must be provided which can be abattery, connection to a power line, solar power, energy harvested fromthe environment via vibration, for example, unless the RFID is based onSAW technology. For SAW technology reading ranges may extend to tens ofmeters. Greater distances can be achieved using reflectors or reflectingantennas.

Electronic circuitry, not shown, associated with the interrogator 160and/or 161 would determine the precise distance from the vehicle to theRFID tag 151, 152, 153 based on the round trip time of flight. This willprovide the precise distance to the three RFID tags 151, 152, 153. Onceagain, a second interrogator 161 can also be used, in which case, itcould be a receiver only and would provide redundancy information to themain interrogator 160 and also provide a second measure of the distanceto each of the RFID tags. Based on the displacement of the two receivers160, 161, the angular location of each RFID tag relative into thevehicle can be determined providing further redundant information as tothe position of the vehicle relative to the tags.

Radar corner reflectors can be placed on poles or other convenientplaces such that a radar beam pointed upwards at an angle, such as 30 to45 degrees from the vehicle, will cause the beam to illuminate thereflector and thereby cause a reflection to return to the vehicle.Through well-known methods, the distance to the reflector can beaccurately measured with pulse radar, modulated radar and phasemeasurements or noise radar and correlations measurements. In such amanner, the host vehicle can determine its position relative to one ormore such reflectors and if the location of the reflector(s) is knownand recorded on the map database, the vehicle can determine its positionto within about 2 centimeters. The more reflectors that are illuminated,the better the accuracy of vehicle location determination. Thereflectors can be simple corner reflectors or a group of reflectors canbe provided giving a return code to the host vehicle.

Using the PPS system, a vehicle can precisely determine its locationwithin two centimeters or better relative to the MIR, RFID tags or radarand reflectors and since the precise location of these devices haspreviously been recorded on the map database, the vehicle will be ableto determine its precise location on the surface of the earth. With thisinformation, the vehicle will thereafter be able to use the carrier wavephase to maintain its precise knowledge of its location, as discussedabove, until the locks on the satellites are lost. Similarly, thevehicle 18 can broadcast this information to vehicle 26, for example,permitting a vehicle that has not passed through the PPS triad to alsogreatly improve the accuracy with which it knows its position. Eachvehicle that has recently passed through a PPS triad now becomes adifferential GPS station for as long as the satellite locks aremaintained. Therefore, through inter-vehicle communications, allvehicles in the vicinity can also significantly improve their knowledgeof their position accuracy resulting in a system which is extremelyredundant and therefore highly reliable and consistent with the “Road toZero Fatalities”™ process. Once this system is operational, it isexpected that the U.S. government and other governments will launchadditional GPS type satellites, each with more civilian readablefrequencies, or other similar satellite systems, further strengtheningthe system and adding further redundancy eventually resulting in ahighly interconnected system that approaches 100% reliability and, likethe Internet, cannot be shut down.

As the system evolves, the problems associated with urban canyons,tunnels, and other obstructions to satellite view will be solved by theplacement of large numbers of PPS stations, or other devices providingsimilar location information.

The final PPS system uses reflected energy from the environment tocreate a signature that can be matched with a recorded signature using atechnology such as adaptive associative memories (AAM), or equivalentincluding correlation. Since the AAM was discussed above, thecorrelation system will be discussed here. As the mapping vehicletraverses the roadway, it can record the distance to various roadsideobjects as a continuous signal having peaks and valleys. In fact,several such signatures can economically be recorded such thatregardless of where on the roadway a subsequent vehicle appears, it willrecord a similar signature. The signature can be enhanced if dualfrequency terahertz is used since the reflectance from an object canvary significantly from one terahertz frequency to another depending onthe composition of the object. Thus for one frequency, a metal and awood object may both be highly reflective while at another frequency,there can be a significant difference. Significantly more information isavailable when more than one frequency is used.

Using the correlation system, a vehicle will continuously be comparingits received signature at a particular location to the previouslyrecorded signature and shifting the two relative to each other until thebest match occurs. Since this will be done continuously and since wewill know the velocity of the vehicle, it should never deviatesignificantly from the recorded position and thus the vehicle willalways have a non-GPS method of determining its exact location. Thereare certain areas where the signature matching may be problematic suchas going by a wheat field or the ocean. Fortunately, such wide openspaces are precisely where the GPS satellite system should work best andsimilarly the places where the signature method works best is where theGPS has problems. Thus, the systems are complementary. In most places,both systems will work well providing a high degree of redundancy.

Many mathematical methods exist for determining the best shift of thetwo signatures (the previously recorded one and a new one) and thereforethe various correlation methods will not be presented here.

Although the system has been illustrated for use with automobiles, thesame system would apply for all vehicles including trucks, trains aneven airplanes taxiing on runways. It also would be useful for use withcellular phones and other devices carried by humans. The combination ofthe PPS system and cellular phones permits the precise location of acellular phone to be determined within centimeters by an emergencyoperator receiving a 911 call, for example. Such RFID tags can beinexpensively placed both inside and outside of buildings, for example.

The range of RFID tags is somewhat limited to approximately 10 metersfor current technology. If there are obstructions preventing a clearview of the RFID tag by the interrogator, the distance becomes less. Forsome applications where it is desirable to use larger distances, batterypower can be provided to the RFID tags. In this case, the interrogatorwould send a pulse to the tag that would turn on the tag and at aprecise, subsequent time the tag would transmit an identificationmessage. In some cases, the interrogator itself can provide the power todrive the RFID circuitry, in which case the tag would again operate inthe transponder mode as opposed to the reflective mode.

The RFID tags discussed herein can be either the electronic circuit orSAW designs.

From the above discussion, those skilled in the art will understand thatother devices can be interrogated by a vehicle traveling down the road.Such devices might include various radar types or designs of reflectors,mirrors, other forms of transponders, or other forms of energyreflectors. All such devices are contemplated by this invention and theinvention is not limited to be specific examples described. Inparticular although various frequencies including radar, terahertz andinfrared have been discussed, this invention is not limited to thoseportions of the electromagnetic spectrum. In particular, the X-ray bandof frequencies may have some particular advantages for some external andinterior imaging applications.

Any communication device can be coupled with an interrogator thatutilizes the MIR, radar or RFID PPS system described above. Many devicesare now being developed that make use of the Bluetooth communicationspecification. All such Bluetooth enabled devices can additionally beoutfitted with a PPS system permitting the location of the Bluetoothdevice to be positively determined. This enabling technology will permita base station to communicate with a Bluetooth-enabled device whoselocation is unknown and have the device transmit back its preciselocation on the surface of the earth. As long as the Bluetooth-enableddevice is within the range of the base station, its location can beprecisely determined. Thus, the location of mobile equipment in afactory, packages within the airplane cargo section, laptop computers,cell phones, PDAs, and eventually even personal glasses or car keys orany device upon which a Bluetooth-enabled device can be attached can bedetermined. Actually, this invention is not limited to Bluetooth devicesbut encompasses any device that can communicate with any other devices.

Once the location of an object can be determined, many other servicescan be provided. These include finding the device, or the ability toprovide information to that device or to the person accompanying thatdevice such as the location of the nearest bathroom, restaurant, or theability to provide guided tours or other directions to people travelingto other cities, for example.

A particularly important enhancement to the above-described system usesprecise positioning technology independent of GPS. The precisepositioning system, also known as the calibration system, generallypermits a vehicle to precisely locate itself independently of the IMU orDGPS systems.

One example of this technology involves the use of a radar and reflectorsystem wherein radar transceivers are placed on the vehicle that sendradar waves to reflectors that are mounted at the side of road. Thelocation of reflectors either is already precisely known or isdetermined by the mapping system during data acquisition process. Theradar transceivers transmit a pulse, code or frequency or noisemodulated radar signal to the road-mounted reflectors, typically cornerreflectors, which reflect a signal back to the radar transceiver. Thispermits the radar system to determine the precise distance from thetransceiver to the reflector by either time-of-flight or phase methods.Note that although radar will be used below in the illustrations,terahertz can also be used and thus the word “radar” will be used tocover both parts of the electromagnetic spectrum.

In one possible implementation, each vehicle is equipped with two radardevices operating in the 24–77 GHz portion of the spectrum. Each radarunit will be positioned on the vehicle and aimed outward, slightlyforward and up toward the sides of the roadway. Poles would bepositioned along the roadway at appropriate intervals and would havemultiple corner cube radar reflectors mounted thereon to thereto,possibly in a vertical alignment. The lowest reflector on the pole wouldbe positioned so that the vehicle radar will illuminate the reflectorwhen the vehicle is in the lane closest to the pole. The highestreflector on the pole would be positioned so that the vehicle radar willilluminate the reflector when the vehicle is in the lane most remotefrom the pole. The frequency of the positioning of the poles will bedetermined by such considerations as the availability of light poles orother structures currently in place, the probability of losing access toGPS satellites, the density of vehicle traffic, the accuracy of the IMUand other similar considerations. Initially, rough calculations havefound that a spacing of about ¼ mile would likely be acceptable.

If the precise location of the reflectors has been previously determinedand is provided on a road map database, then the vehicle can use thisinformation to determine its precise location on the road. In a moretypical case, the radar reflectors are installed and the mapping vehicleknows its location precisely from the differential GPS signals and theIMU, which for the mapping vehicle is typically of considerably higheraccuracy than will be present in the vehicles that will later use thesystem. As a result, the mapping vehicle can also map a tunnel, forexample, and establish the locations of radar reflectors that will laterbe used by non-mapping vehicles to determine their precise location whenthe GPS and differential GPS signals are not available. Similarly, suchradar reflectors can be located for an appropriate distance outside ofthe tunnel to permit an accurate location determination to be made by avehicle until it acquires the GPS and differential GPS signals. Such asystem can also be used in urban canyons and at all locations where theGPS signals can be blocked or are otherwise not available. Since thecost of radar reflectors is very low, it is expected that eventuallythey will be widely distributed on roads in the U.S.

The use of radar and reflectors for precise positioning is only one ofmany systems being considered for this purpose. Others include markingson roadway, RFID tags, laser systems, laser radar and reflectors,magnetic tags embedded in the roadway, magnetic tape, etc. The radar andreflector technology has advantages over some systems in that it is notseriously degraded by bad weather conditions, is not affected if coveredwith snow, does not pose a serious maintenance problem, and other costand durability features. Any movement in the positioning of thereflectors can be diagnosed from vehicle PPS-mounted systems.

The radar transceivers used are typically mounted on either side ofvehicle and pointed upward at between 30 and 60 degrees. They aretypically aimed so that they project across the top of the vehicle sothat several feet of vertical height can be achieved prior to passingover adjacent lanes where the signal could be blocked by a truck, forexample. Other mounting and aiming systems can be used.

The radar reflectors are typically mounted onto a pole, building,overpass, or other convenient structure. They can provide a return codeby the placement of several such reflectors such that the reflectedpulse contains information that identifies this reflector as aparticular reflector on the map database. This can be accomplished innumerous ways including the use of a collection of radar reflectors in aspaced-apart geometric configuration on a radius from the vehicle. Thepresence or absence of a reflector can provide a returned binary code,for example.

The operation of the system is as follows. A vehicle traveling down aroadway in the vicinity of the reflector poles would transmit radarpulses at a frequency of perhaps once per microsecond. These radarpulses would be encoded, perhaps with noise or code modulation, so thateach vehicle knows exactly what radar returns are from itstransmissions. As the vehicle approaches a reflector pole, it will beginto receive reflections based on the speed of the vehicle. By observing aseries of reflections, the vehicle software can select either themaximum amplitude reflection or the average or some other scheme todetermine the proper reflection to consider. The radar pulse will alsobe modulated to permit a distance to the reflector calculation to bemade based on the phase of the returned signal or through correlation.Thus, as a vehicle travels down the road and passes a pair of reflectorpoles, it will be able to determine its longitudinal position on theroadway based on the pointing angle of the radar devices and theselected maximum return as described above. It will also be able todetermine its lateral position on the roadway based on the measureddistance from the radar to the reflector.

Each reflector pole will have multiple reflectors determined byintersections of the radar beam from the vehicle traveling in theclosest and furthest lanes. The spacing of reflectors on the pole wouldbe determined by the pixel diameter of the radar beam. For example, atypical situation may require radar reflectors beginning at 4 m from theground and ending at 12 m with a reflector every one-meter. For theinitial demonstrations, it is expected that existing structures will beused. The corner cube radar reflectors are very inexpensive so thereforethe infrastructure investment will be small as long as existingstructures can be used. In the downtown areas of cities, buildings etc.can also be used as reflector locations.

To summarize this aspect of the invention, an inexpensive infrastructureinstallation concept is provided which will permit a vehicle to send aradar pulse and receive a reflection wherein the reflection isidentifiable as the reflection from the vehicle's own radar and containsinformation to permit an accurate distance measurement. The vehicle canthus locate itself accurately longitudinally and laterally along theroad. A variation of the PPS system using a signature from acontinuously reflected laser or radar has been discussed above and willnot be repeated here.

FIG. 19 shows a variety of roads and vehicles operating on those roadsthat are in communication with a vehicle that is passing through aPrecise Positioning Station (PPS). The communication system used isbased on noise modulated spread spectrum technologies such as describedin the above-listed papers by Lukin et al.

FIG. 20 shows a schematic of the operation of a communication and/orinformation system and method in accordance with the invention.Transmitters are provided, for example at fixed locations and/or invehicles or other moving objects, and data about each transmitter, suchas its location and an identification marker, is generated at 240. Thelocation of the transmitter is preferably its GPS coordinates asdetermined, for example, by a GPS-based position determining system(although other position determining systems can alternatively oradditionally be used). The data may include, when the transmitter is amoving vehicle, the velocity, the direction of travel, the estimatedtravel path and the destination of the vehicle. The data is encoded at242 using coding techniques such as those described above, e.g., phasemodulation of distance or time between code transmissions, phase oramplitude modulation of the code sequences themselves, changes of thepolarity of the entire code sequence or the individual code segments, orbandwidth modulation of the code sequence. The coded data is transmittedat 244 using, e.g., noise or pseudo-noise radar.

Instead of data about each transmitter being generated at 240, generaldata for transmission could also be generated such as road conditioninformation or traffic information.

A vehicle 246 includes an antenna 248 coupled to a control module,control unit, processor or computer 250. The antenna 248 receivestransmissions (waves) including transmissions 252 when in range of thetransmitters. The processor 250 analyzes the transmissions 252. Suchanalysis may include a determination whether any transmissions are fromtransmitters within a pre-determined area relative to the vehicle,transmitters situated within a pre-determined distance from the vehicle,from transmitters traveling in a direction toward the vehicle's currentposition, transmitters traveling in a direction toward the vehicle'sprojected position based on its current position and velocity, the anglebetween the transmitter and the vehicle, and any combinations of suchdeterminations. Other analyses could be whether any are from particulartransmitters which might be dedicated to the transmission of roadconditions data, traffic data, map data and the like. Once the processor250 ascertains a particular transmission of interest (for operation ofthe vehicle, or for any other pre-determined purpose), it extracts theinformation coded in the transmission, but does not extract informationcoded in transmission from transmitters which are not of interest, e.g.,those from a location outside of the pre-determined area. It knows thecode because the code is provided by the transmission, i.e., the initialpart of the transmission 252 a contains data on the location of thetransmitter and the code is based on the location of the transmitter. Assuch, once the initial part of the transmission is received and thelocation of the transmitter extracted, the code for the remainder of thetransmission 252 b can be obtained.

In this manner, the extraction of information from radio frequency wavetransmission is limited based on a threshold determination (a filter ofsorts) as to whether the transmission is of potential interest, e.g., tothe operation of the vehicle based on its position. To enable thisthreshold determination from the analysis of the waves or filtering ofinformation, the initial part of the transmission 252 a can be providedwith positional information about the transmitter and informationnecessitated by the information transferring arrangement (communicationprotocol data) and the remainder of the transmission 252 b provided withadditional information of potential interest for operation of thevehicle. The information contained in initial part of each transmission(or set of waves) is extracted to determine whether the information inthe final part of the transmission is of interest. If not, theinformation in the final part of the transmission is not extracted. Thisreduces processing time and avoids the unnecessary extraction of mostlyif not totally irrelevant information. An information filter istherefore provided.

Further, the antenna 248 serves as a transmitter for transmittingsignals generated by the processor 250. The processor 248 is constructedor programmed to generate transmissions or noise signals based on itslocation, determined by a position determining device 254 in any knownmanner including those disclosed herein, and encode information aboutthe vehicle in the signals. The information may be an identificationmarker, the type of vehicle, its direction, its velocity, its proposedcourse, its occupancy, etc. The processor 248 can encode the informationin the signals in a variety of methods as disclosed above in the samemanner that the data about the transmitter is encoded. Thus, theprocessor 248 not only interprets the signals and extracts information,it also is designed to generate appropriate noise or otherwise codedsignals which are then sent from the antenna 248.

Consider the case where the automobile becomes a pseudolite or a DGPSequivalent station since it has just determined its precise locationfrom the PPS. Thus the vehicle can broadcast just like a pseudolite. Asthe vehicle leaves the PPS station, its knowledge of its absoluteposition will degrade with time depending on the accuracy of its clockand inertial guidance system and perhaps its view of the satellites orother pseudolites. In some cases, it might even be possible to eliminatethe need for satellites if sufficient PPS positions exist.

Another point is that the more vehicles that are in the vicinity of aPPS, the higher the likelihood that one of the vehicles will knowprecisely where it is by being at or close to the PPS and thus the moreaccurately every vehicle in the vicinity would know its own location.Thus, the more vehicles on the road, the accuracy with which everyvehicle knows its location increases. When only a single vehicle is onthe road, then it really doesn't need to know its position nearly asaccurately at least with regard to other vehicles. It may still need toknow its accuracy to a comparable extent with regard to the road edges.

5. Radar and Laser Radar Detection and Identification of ObjectsExternal to the Vehicle

5.1 Sensing of Non-RtZF™ Equipped Objects

Vehicles with the RtZF™ system in accordance with the invention mustalso be able to detect those vehicles that do not have the system aswell as pedestrians, animals, bicyclists, and other hazards that maycross the path of the equipped vehicle.

Systems based on radar have suffered from the problem of being able tosufficiently resolve the images which are returned to be able toidentify the other vehicles, bridges, etc. except when they are close tothe host vehicle. One method used for adaptive cruise control systems isto ignore everything that is not moving. This, of course, leads toaccidents if this were used with the instant invention. The problemstems from the resolution achievable with radar unless the antenna ismade very large or the object is close. Since this is impractical foruse with automobiles, only minimal collision avoidance can be obtainedusing radar.

Optical systems can provide the proper resolution but may requireillumination with a bright light or laser. If the laser is in theoptical range, there is a danger of causing eye damage to pedestrians orvehicle operators. At a minimum, it will be distracting and annoying toother vehicle operators. A laser operating in the infrared part of theelectromagnetic spectrum avoids the eye danger problem, provided thefrequency is sufficiently far from the visible, and, since it will notbe seen, it will not be annoying. If the IR light is sufficientlyintense to provide effective illumination for the host vehicle, it mightbe a source of blinding light for the system of another vehicle.Therefore a method of synchronization may be required. This could takethe form of an Ethernet protocol, for example, where when one vehicledetects a transmission from another then it backs off and transmits at arandom time later. The receiving electronics would then only be activewhen the return signal is expected.

Another problem arises when multiple vehicles are present that transmitinfrared at the same time if there is a desire to obtain distanceinformation from the scene. In this case, each vehicle needs to be ableto recognize its transmission and not be fooled by transmissions fromanother vehicle. This can be accomplished, as discussed above, throughthe modulation scheme. Several such schemes would suffice with apseudo-noise or code modulation as the preferred method for the presentinvention. This can also be accomplished if each vehicle accuratelyknows its position and controls its time of transmission according to analgorithm that time multiplexes transmissions based on the geographicallocation of the vehicle. Thus if multiple vehicles are sensed in a givengeographical area, they each can control their transmissions based on acommon algorithm that uses the GPS coordinates of the vehicle to set thetime slot for transmission so as to minimize interference betweentransmissions from different vehicles. Other multiplexing methods canalso be used such as FDMA, CDMA or TDMA, any of which can be based onthe geographical location of the vehicles.

Infrared and terahertz also have sufficient resolution so that patternrecognition technologies can be employed to recognize various objects,such as vehicles, in the reflected image as discussed above. Infraredhas another advantage from the object recognition perspective. Allobjects radiate and reflect infrared. The hot engine or tires of amoving vehicle in particular are recognizable signals. Thus, if the areaaround a vehicle is observed with both passive and active infrared, moreinformation can be obtained than from radar, for example. Infrared isless attenuated by fog than optical frequencies, although it is not asgood as radar. Infrared is also attenuated by snow but at the properfrequencies it has about five times the range of human sight. Terahertzunder some situations has an effective range of as much as severalhundred times that of human sight. Note, as with radar, infrared andterahertz can be modulated with noise, pseudonoise, or other distinctivesignal to permit the separation of various reflected signals fromdifferent transmitting vehicles.

An example of such an instrument is made by Sumitomo Electric and issufficient for the purpose here. The Sumitomo product has beendemonstrated to detect leaves of a tree at a distance of about 300meters. The product operates at a 1.5 micron wavelength.

This brings up a philosophical discussion about the trade-offs betweenradar with greater range and infrared laser radar, or lidar, with morelimited range but greater resolution. At what point should drivingduring bad weather conditions be prohibited? If the goal of ZeroFatalities™ is to be realized, then people should not be permitted tooperate their vehicles during dangerous weather conditions. This mayrequire closing roads and highways prior to the start of suchconditions. Under such a policy, a system which accurately returnsimages of obstacles on the roadway that are two to five times the visualdistance should be adequate. In such a case, radar would not benecessary.

5.2 Laser and Terahertz Radar Scanning System

Referring to FIG. 25, a digital map (116) can be provided and when thevehicle's position is determined (118), e.g., by a GPS-based system, thedigital map can be used to define the field (122) that the laser orterahertz radar scanner (102) will interrogate. Note, when the termscanner is used herein, it is not meant to imply that the beam is sonarrow as to require a back and forth motion (a scan) in order tocompletely illuminate an object of interest. To the contrary, theinventions herein are not limited to a particular beam diameter otherthan that required for eye safety. Also a scanner may be limited to anangular motion that just covers a vehicle located 100 meters, forexample, from the transmitting vehicle, which may involve no angularmotion of the scanner at all, or to an angular motion that covers 90 ormore degrees of the space surrounding the transmitting vehicle. Throughthe use of high-powered lasers and appropriate optics, an eye safe laserbeam can be created that is 5 cm in diameter, for example, with adivergence angle less than one degree. Such an infrared spotlightrequires very little angular motion to illuminate a vehicle at 100meters, for example.

Generally herein, when laser radar, or lidar, is used it will also meana system based on terahertz where appropriate. The laser radar or lidarscanner will return information as to distance to an object in thescanned field, e.g., laser beam reflections will be indicative ofpresence of object in path of laser beam (104) and from thesereflections, information such as the distance between the vehicle andthe object can be obtained. This will cover all objects that are on oradjacent to the highway. The laser pulse can be a pixel that is twocentimeters or 1 meter in diameter at 50 meters, for example and thatpixel diameter can be controlled by the appropriate optical system thatcan include adaptive optics and liquid lenses (such as described in“Liquid lens promises cheap gadget optics”, NewScientist.com newsservice, Mar. 8, 2004). The scanner must scan the entire road at such aspeed that the motion of the car can be considered insignificant.Alternately, a separate aiming system that operates at a much lowerspeed, but at a speed to permit compensation for the car angle changes,may be provided. Such an aiming system is also necessary due to the factthat the road curves up and down. Therefore two scanning methods, one aslow, but for large angle motion and the other fast but for small anglesmay be required. The large angular system requires a motor drive whilethe small angular system can be accomplished through the use of anacoustic wave system, such as Lithium Niobate (LiNbO₃), which is used todrive a crystal which has a large refractive index such as Telluriumdioxide. Other acoustic optical systems can also be used as scanners.

For these systems, frequently some means is needed to stabilize theimage and to isolate it from vehicle vibrations. Several suchstabilization systems have been used in the past and would be applicablehere including a gyroscopic system that basically isolates the imagingsystem from such vibrations and keeps it properly pointed, apiezoelectric system that performs similarly, or the process can beaccomplished in software where the image is collected regardless of thevibration but where the image covers a wider field of view then isnecessary and software is used to select the region of interest.

Alternately, two systems can be used, a radar system for interrogatinglarge areas and a laser radar for imaging smaller areas. Either or bothsystems can be range gated and noise or pseudonoise modulated.

The laser radar scanner can be set up in conjunction with a range gate(106) so that once it finds an object, the range can be narrowed so thatonly that object and other objects at the same range, 65 to 75 feet forexample, are allowed to pass to the receiver. In this way, an image of avehicle can be separated from the rest of the scene for identificationby pattern recognition software (108). Once the image of the particularobject has been captured, the range gate is broadened, to about 20 to500 feet for example, and the process repeated for another object. Inthis manner, all objects in the field of interest to the vehicle can beseparated and individually imaged and identified. Alternately, a schemebased on velocity can be used to separate a part of one object from thebackground or from other objects. The field of interest, of course, isthe field where all objects with which the vehicle can potentiallycollide reside. Particular known and mapped features on the highway canbe used as aids to the scanning system so that the pitch and perhapsroll angles of the vehicle can be taken into account. Once the identityof the object is known, the potential for a collision between thevehicle and that object and/or consequences of a potential collisionwith that object are assessed, e.g., by a control module, control unitor processor (112). If collision is deemed likely, countermeasures areeffected (114), e.g., activation of a driver alert system and/oractivation of a vehicle control system to alter the travel of thevehicle (as discussed elsewhere herein).

Range gates can be achieved as high speed shutters by a number ofdevices such as liquid crystals, garnet films, Kerr and Pockel cells oras preferred herein as described in patents and patent applications of3DV Systems Ltd., Yokneam, Israel including U.S. Pat. No. 6,327,073,U.S. Pat. No. 6,483,094, U.S. 2002/0185590, WO98/39790, WO97/01111,WO97/01112 and WO97/01113.

Prior to the time that all vehicles are equipped with the RtZF™ systemdescribed above, roadways will consist of a mix of vehicles. In thisperiod, it will not be possible to totally eliminate accidents. It willbe possible to minimize the probability of having an accident however,if a laser radar or Lidar system similar to that described in Shaw (U.S.Pat. No. 5,529,138), or more recently in various patents and patentapplications of Ford Global Technologies such as U.S. Pat. No.6,690,017, U.S. Pat. No. 6,730,913, U.S. 2003/0034462, U.S. 2003/0155513and U.S. 2003/0036881, with some significant modifications is used. Itis correctly perceived by Shaw that the dimensions of a radar beam aretoo large to permit distinguishing various objects which may be on theroadway in the path of the instant vehicle. Laser radar provides thenecessary resolution that is not provided by radar. Laser radar as usedin the present invention however would acquire significantly more datathan anticipated by Shaw. Sufficient data in fact would be attained topermit the acquisition of a three-dimensional image of all objects inthe field of view. The X and Y dimensions of such objects would, ofcourse, be determined knowing the angular orientation of the laser radarbeam. The longitudinal or Z dimension can be obtained by such methods astime-of-flight of the laser beam to a particular point on the object andreflected back to the detector, by phase methods or by range gating. Allsuch methods are described elsewhere herein and in the patents listedabove.

At least two methods are available for resolving the longitudinaldimension for each of the pixels in the image. In one method, a laserradar pulse having a pulse width of one to ten nanoseconds, for example,can be transmitted toward the area of interest and as soon as thereflection is received and the time-of-flight determined, a new pulsewould be sent at a slightly different angular orientation. The laser,therefore, would be acting as a scanner covering the field of interest.A single detector could then be used, if the pixel is sufficientlysmall, since it would know which pixel was being illuminated. Thedistance to the reflection point could be determined by time-of-flightthus giving the longitudinal distance to all points in view on theobject.

Alternately, the entire area of interest can be illuminated and an imagefocused on a CCD or CMOS array. By checking the time-of-flight to eachpixel, one at a time, the distance to that point on the vehicle would bedetermined. A variation of this would be to use a garnet crystal as apixel shutter and only a single detector. In this case, the garnetcrystal would permit the illumination to pass through one pixel at atime through to a detector. A preferred method, however, for thisinvention is to use range gating as described elsewhere herein.

Other methods of associating a distance to a particular reflectionpoint, of course, can now be performed by those skilled in the artincluding variations of the above ideas using a pixel mixing device(such as described in Schwarte, R. “A New Powerful Sensory Tool inAutomotive Safety Systems Based on PMD-Technology”, S-TEC GmbHProceedings of the AMAA 2000) or variations in pixel illumination andshutter open time to determine distance through comparison of rangegated received reflected light. In the laser scanning cases, the totalpower required from the laser is significantly less than in the areaillumination design. However, the ability to correctly change thedirection of the laser beam in a sufficiently short period of timecomplicates the scanning design. The system can work approximately asfollows: The entire area in front of the instant vehicle, perhaps asmuch as a full 180 degree arc in the horizontal plane can be scanned forobjects using either radar or laser radar. Once one or more objects hadbeen located, the scanning range can be severely limited to basicallycover that particular object and some surrounding space using laserradar. Based on the range to that object, a range gate can be used toeliminate all background and perhaps interference from other objects. Inthis manner, a very clear picture or image of the object of interest canbe obtained as well as its location and, through the use of a neuralnetwork, combination neural network or optical correlation or otherpattern of recognition system, the identity of the object can beascertained as to whether it is a sign, a truck, an animal, a person, anautomobile or other object. The identification of the object will permitan estimate to be made of the object's mass and thus the severity of anypotential collision.

Once a pending collision is identified, this information can be madeavailable to the driver and if the driver ceases to heed the warning,control of the vehicle could be taken from him or her by the system. Theactual usurpation of vehicle control, however, is unlikely initiallysince there are many situations on the highway where the potential for acollision cannot be accurately ascertained. Consequently, this systemcan be thought of as an interim solution until all vehicles have theRtZF™ system described above.

To use the laser radar in a scanning mode requires some mechanism forchanging the direction of the emitted pulses of light. Oneacoustic-optic method of using an ultrasonic wave to change thediffraction angle of a Tellurium dioxide crystal is disclosed elsewhereherein. This can also be done in a variety of other ways such as throughthe use of a spinning multifaceted mirror, such as is common with laserscanners and printers. This mirror would control the horizontalscanning, for example, with the vertical scanning controlled though astepping motor or the angles of the different facets of the mirror canbe different to slightly alter the direction of the scan, or by othermethods known in the art. Alternately, one or more piezoelectricmaterials can be used to cause the laser radar transmitter to rotateabout a pivot point. A rotating laser system, such as described in Shawis the least desirable of the available methods due to the difficulty inobtaining a good electrical connection between the laser and the vehiclewhile the laser is spinning at a very high angular velocity. Anotherpromising technology is to use MEMS mirrors to deflect the laser beam inone or two dimensions.

Although the system described above is intended for collision avoidanceor at least the notification of a potential collision, when the roadwayis populated by vehicles having the RtZF™ system and vehicles which donot, its use is still desirable after all vehicles are properlyequipped. It can be used to search for animals or other objects whichmay be on or crossing the highway, a box dropping off of a truck forexample, a person crossing the road who is not paying attention totraffic. Motorcycles, bicycles, and other non-RtZF equipped vehicles canalso be monitored.

One significant problem with all previous collision avoidance systemswhich use radar or laser radar systems to predict impacts with vehicles,is the inability to know whether the vehicle that is being interrogatedis located on the highway or is off the road. In at least one system ofthe present invention, the location of the road at any distance ahead ofthe vehicle would be known precisely from the sub-meter accuracy maps,so that the scanning system can ignore, for example, all vehicles onlanes where there is a physical barrier separating the lanes from thelane on which the subject vehicle is traveling. This, of course, is acommon situation on super highways. Similarly, a parked vehicle on theside of the road would not be confused with a stopped vehicle that is inthe lane of travel of the subject vehicle when the road is curving. Thispermits the subject invention to be used for automatic cruise control.In contrast with radar systems, it does not require that vehicles in thepath of the subject vehicle be moving, so that high speed impacts intostalled traffic can be avoided.

If a system with a broader beam to illuminate a larger area on the roadin front of the subject vehicle is used, with the subsequent focusing ofthis image onto a CCD or CMOS array, this has an advantage of permittinga comparison of the passive infrared signal and the reflection of thelaser radar active infrared. Metal objects, for example appear cold topassive infrared. This permits another parameter to be used todifferentiate metallic objects from non-metallic objects such as foliageor animals such as deer. The breadth of the beam can be controlled andthereby a particular object can be accurately illuminated. With thissystem, the speed with which the beam steering is accomplished can bemuch slower. Both systems can be combined into the maximum amount ofinformation to be available to the system.

Through the use of range gating, objects can be relatively isolated fromthe environment surrounding it other than for the section of highwaywhich is at the same distance. For many cases, a properly trained neuralnetwork or other pattern recognition system can use this data andidentify the objects. An alternate approach is to use the Fouriertransform of the scene as input to the neural network or other patternrecognition system. The advantages of this latter approach are that theparticular location of the vehicle in the image is not critical foridentification. Note that the Fourier transform can be accomplishedoptically and optically compared with stored transforms using a garnetcrystal or garnet films, for example, as disclosed in U.S. Pat. No.5,473,466.

At such time when the system can take control of the vehicle, it will bepossible to have much higher speed travel. In such cases, all vehicleson the controlled roadway will need to have the RtZF™ or similar systemas described above. Fourier transforms of the objects of interest can bedone optically though the use of a diffraction system. The Fouriertransform of the scene can then be compared with the library of theFourier transforms of all potential objects and, through a system usedin military target recognition, multiple objects can be recognized andthe system then focused onto one object at time to determine the degreeof threat that it poses.

Of particular importance is the use of a high powered laser radar suchas a 30 to 100 watt laser diode in an expanded beam form to penetratefog, rain and snow through the use of range gating. If a severalcentimeter diameter beam is projected from the vehicle in the form ofpulses of from 1 to 10 nanoseconds long, for example, and the reflectedradiation is blocked except that from the region of interest, an imagecan still be captured even though it cannot be seen by the human eye.This technique significantly expands the interrogation range of thesystem and, when coupled with the other imaging advantages of laserradar, offers a competitive system to radar and may in fact render theautomotive use or radar unnecessary. One method is to use the techniquesdescribed in the patents to 3DV listed above. In one case, for example,if the vehicle wishes to interrogate an area 250 feet ahead, a 10nanosecond square wave signal can be used to control the shutter whichis used both for transmission and reception and where the off period canbe 480 nanoseconds. This can be repeated until sufficient energy hasbeen accumulated to provide for a good image. In this connection, a highdynamic range camera may be used such as that manufactured by IMS chipsof Stuttgart, Germany as mentioned above. Such a camera is now availablewith a dynamic range of 160 db.

These advantages are also enhanced when the laser radar system describedherein is used along with the other features of the RtZF™ system such asaccurate maps and accurate location determination. The forward lookinglaser radar system can thus concentrate its attention to the knownposition of the roadway ahead rather than on areas where there can be nohazardous obstacles or threatening vehicles.

5.3 Blind Spot Detection

The RtZF™ system of this invention also can eliminate the need for blindspot detectors such as discussed in U.S. Pat. No. 5,530,447 toHenderson. Alternately, if a subset of the complete RtZF™ system isimplemented, as is expected in the initial period, the RtZF™ system canbe made compatible with the blind spot detector described in the '447patent.

One preferred implementation for blind spot monitoring as well as formonitoring other areas near the vehicle is the use of range gated laserradar using a high power laser diode and appropriate optics to expandthe laser beam to the point where the transmitted infrared energy persquare millimeter is below eye safety limits. Such a system is describedabove.

5.4 Anticipatory Sensing—Smart Airbags, Evolution of the System

A key to anticipating accidents is to be able to recognize andcategorize objects that are about to impact a vehicle as well as theirrelative velocity. As set forth herein and in current assignee's patentsand patent applications referenced above, this can best be done using apattern recognition system such as a neural network, combination neuralnetwork, optical correlation system, sensor fusion and relatedtechnologies. The data for such a pattern recognition system can bederived from a camera image but such an image can be overwhelmed byreflected light from the sun. In fact, lighting variations in generalplague camera-based images resulting in false classifications or even noclassification. Additionally, camera-based systems are defeated by poorvisibility conditions and, additionally, have interference problems whenmultiple vehicles have the same system which may require asynchronization, taking time away from the critical anticipatory sensingfunction.

To solve these problems imaging systems based of millimeter wave radar,laser radar (lidar) and more recently terahertz radar can be used. Allthree systems generally work for anticipatory sensors since the objectsare near the vehicle where even infrared scanning laser radar in anon-range gated mode has sufficient range in fog. Millimeter wave radaris expensive and to obtain precise images, a narrow beam is requiredresulting in large scanning antennas. Laser radar systems are lessexpensive and since the beams are formed using optic technology, theyare smaller and easier to manipulate.

When computational power is limited, it is desirable to determine theminimum number of pixels that are required to identify an approachingobject with sufficient accuracy to make the decision to take evasiveaction or to deploy a passive restraint such as an airbag. In onemilitary study for anti-tank missiles, it was found that a total of 25pixels are all that is required to identify a tank on a battlefield. Foroptical occupant detection within a vehicle, thousands of pixels aretypically used. Experiments indicate that by limiting the number ofhorizontal scans to three to five, with on the order of 100 to 300pixels per scan that sufficient information is available to find anobject near to the vehicle and in most cases to identify the object.Once the object has been located, then the scan can be confined to theposition of the object and the number of pixels available for analysissubstantially increases. There are obviously many algorithms that can bedeveloped and applied to this problem and it is therefore left to thoseskilled in the art. At least one invention herein is based on the factthat a reasonable number of pixels can be obtained from the reflectionsof electromagnetic energy from an object to render each of the proposedsystems practical for locating, identifying and determining the relativevelocity of an object in the vicinity of a vehicle that poses a threatto impact the vehicle so that evasive action can be taken or a passiverestraint deployed. See the discussion in section 5.5 below for apreferred implementation.

The RtZF™ system is also capable of enhancing other vehicle safetysystems. In particular, by knowing the location and velocity of othervehicles, for those cases where an accident cannot be avoided, the RtZF™system will in general be able to anticipate a crash and make anassessment of the crash severity using, for example, neural networktechnology. Even with a limited implementation of the RtZF™ system, asignificant improvement in smart airbag technology results when used inconjunction with a collision avoidance system such as described in Shaw(U.S. Pat. No. 5,314,037 and U.S. Pat. No. 5,529,138) and a neuralnetwork anticipatory sensing algorithm such as disclosed in U.S. Pat.No. 6,343,810 to Breed. A further enhancement would be to code avehicle-to-vehicle communication signal from RtZF™ system-equippedvehicles with information that includes the size and approximate weightof the vehicle. Then, if an accident is inevitable, the severity canalso be accurately anticipated and the smart airbag tailored to thepending event. Information on the size and mass of a vehicle can also beimplemented as an RFID tag and made part of the license plate.

Recent developments by Mobileye (www.mobileye.com) illustrate a methodof obtaining the distance to an object and thus the relative velocity.Although this technique has many limitations, it may be useful in someimplementations of one or more of the current inventions.

A further recent development is reported in U.S. patent applicationpublication No. 20030154010, as well as other patents and patentpublications assigned to Ford Global Technologies including U.S. Pat.Nos. 06,452,535, 06,480,144, 06,498,972, 06,650,983, 06,568,754,06,628,227, 06,650,984, 06,728,617, 06,757,611, 06,775,605, 06,801,843,06,819,991, 20030060980, 20030060956, 20030100982, 20030154011,20040019420, 20040093141, 20040107033, 20040111200, and 20040117091. Inthe disclosures herein, emphasis has been placed on identifying apotentially threatening object and once identified, the properties ofthe object such as its size and mass can be determined. An inferiorsystem can be developed as described in U.S. patent applicationpublication No. 20030154010 where only the size is determined. In theinventions described herein, the size is inherently determined duringthe process of imaging the object and identifying it. Also, the Fordpatent publications mention the combined use of a radar or a lidar and acamera system. The combined use of radar and a camera are of courseanticipated herein and in assignee's patents cross-referenced above.

Another recent development by the U.S. Air Force uses a high poweredinfrared laser operating at wavelengths greater than 1.5 microns and afocal plane array as is reported in “Three-Dimensional Imaging” in AFRLTechnology Horizons, April 2004. Such a system is probably too expensiveat this time for automotive applications. This development illustratesthe fact that it is not necessary to limit the lidar to the nearinfrared part of the spectrum and in fact, the further that thewavelength is away from the visible spectrum, the higher the powerpermitted to be transmitted. Also, nothing prevents the use of multiplefrequencies as another method of providing isolation from transmissionsfrom vehicles in the vicinity. As mentioned above for timingtransmissions, the GPS system can also be used to control the frequencyof transmission thus using frequency as a method to preventinterference. The use of polarizing filters to transmit polarizedinfrared is another method to provide isolation between differentvehicles with the same or similar systems. The polarization angle can bea function of the GPS location of the vehicle.

It is the intention of some of the inventions herein to provide a systemthat can be used both in daytime and at night. Other systems areintended solely for night vision such as those disclosed in U.S. Pat.No. 6,730,913, U.S. Pat. No. 6,690,017 and U.S. Pat. No. 6,725,139. Notethat the use of the direction of travel as a method of determining whento transmit infrared radiation, as disclosed in these and other FordGlobal patents and patent applications, can be useful but it fails tosolve the problem of the transmissions from two vehicles traveling inthe same vicinity and direction from receiving reflections from eachothers' transmissions. If the directional approach is used, then someother method is required such as coding the pulses, for example.

U.S. Pat. No. 6,730,913 and U.S. Pat. No. 6,774,367 are representativeof a series of patents awarded to Ford Global Technologies as discussedabove. This patent uses range gating as taught by assignee's earlierpatents. The intent is to supplement the headlights with a night visionsystem for illuminating objects on the roadway in the path of thevehicle but are not seen by the driver and displaying these objects in aheads up display. No attempt is made to locate the eyes of the driverand therefore the display cannot place the objects where they wouldnormally be located in the driver's field of view as taught in thecurrent assignee's other patents. Experiments have shown that withoutthis feature, the night vision system is of little value and may evendistract the driver to where his or her ability to operate the motorvehicle is degraded. Other differences in the '913 and '367 system is anattempt to compensate for falloff in illumination due to distance,neglecting a similar and potentially more serious falloff due toscattering due to fog etc. In at least one of the inventions disclosedherein, no attempt is made to achieve this compensation in a systematicmanner but rather the exposure is adjusted so that a sufficiently brightimage is achieved to permit object identification regardless of thecause of the attenuation. Furthermore, in at least one embodiment, ahigh dynamic range camera is used which automatically compensates formuch of the attenuation and thus permits the minimum exposurerequirements for achieving an adequate image. In at least one of theinventions disclosed herein, the system is used both at night and in thedaytime of locating and identifying objects and, in some cases,initiating an alarm or even taking control of the vehicle to avoidaccidents. None of these objects are disclosed in the '913 or '367 andrelated patents. Additionally, U.S. 20030155513, also part of thisseries of Ford Global patents and applications, describes increasing theillumination intensity based on distance to the desired field of view.In at least one of the inventions disclosed herein, the illuminationintensity is limited by eye safety considerations rather than distanceto the object of interest. If insufficient illumination is not availableon one pulse, additional pulses are provided until sufficientillumination to achieve an adequate exposure is achieved.

If the laser beam diverges, then the amount of radiation per squarecentimeter illuminating a surface will be a function of the distance ofthat surface from the transmitter. If that distance can be measured,then the transmitted power can be increased while keeping the radiationper square centimeter below the eye safe limits. Using this technique,the amount of radiated power can be greatly increased thus enhancing therange of the system in daylight and in bad weather. A lower power pulsewould precede a high power pulse transmitted in a given direction andthe distance measured to a reflective object would be measured and thetransmitted power adjusted appropriately. If a human begins to intersectthe path of transmission, the distance to the human would be measuredbefore he or she could put his or her eye into the transmission path andthe power can be reduced to remain within the safety standards.

It is also important to point out that the inventions disclosed hereinthat use lidar (laser radar or ladar) can be used in a scanning modewhen the area to be covered is larger that the beam diameter or in apointing mode when the beam diameter is sufficient to illuminate thetarget of interest, or a combination thereof.

It can be seen from the above discussion that the RtZF™ system willevolve to solve many safety, vehicle control and ITS problems. Even suchtechnologies as steering and drive by wire will be enhanced by the RtZF™system in accordance with invention since it will automatically adjustfor failures in these systems and prevent accidents.

5.5 A preferred Implementation

FIGS. 21A and 21B illustrate a preferred embodiment of a laser radarsystem having components mounted at the four corners of a vehicle abovethe headlights and tail lights. Laser radar units or assemblies 260 and261 have a scan angle of approximately 150 degrees; however, for someapplications a larger or smaller scanning angle can of course be used.The divergence angle for the beam for one application can be one degreeor less when it is desired to illuminate an object at a considerabledistance from the vehicle such as from less than fifty meters to 200meters or more. In other cases, where objects are to be illuminated thatare closer to the vehicle, a larger divergence angle can be used.Generally, it is desirable to have a field of illumination (FOI)approximately equal to the field of view (FOV) of the camera or otheroptical receiver. FIGS. 22A and 22B illustrate the system of FIGS. 21Aand 21B for vehicles on a roadway. Note that the divergence angle in thehorizontal plane and vertical plane are not necessarily equal.

FIGS. 23A and 23B illustrate an alternative mounting location for laserradar units on or near the roof of a vehicle. They can be either insideor outside of the vehicle compartment. The particular design of thelaser radar assemblies 262 and 263 are similar to those used in FIGS.21A, 21B, 22A and 22B. Although not shown, other geometries are ofcourse possible such as having the laser radar assemblies mounted on ornear the roof for the rear assemblies and above the headlights for thefrontal assemblies or vice versa. Also, although assemblies mounted onthe corners of the vehicle are illustrated, in some cases it may bedesirable to mount laser radar assemblies in the center of the front,back and sides of the vehicle or a combination or center andcorner-mounted laser radar assemblies can be used.

FIG. 24 is a schematic illustration of a typical laser radar assemblyshowing the scanning or pointing system with simplified optics forillustration only. In an actual design, the optics will typicallyinclude multiple lenses. Also, the focal point will typically not beoutside of the laser radar assembly. In this non-limiting example, acommon optical system 267 is used to control a laser light 265 and animager or camera 266. The laser source transmits, usually infrared,light through its optical sub-system 271 which collimates the radiation.The collimated radiation is then reflected off mirror 273 to mirror 274which reflects the radiation to the desired direction through lenssystem 267. The direction of the beam is controlled by motor 272 whichrotates both mirror 274 and optical system 267 to achieve the desiredscanning or pointing angle. The radiation leaves the optical system 267and illuminates the desired object or target 276. The radiationreflected from object 276 can pass back through lens 267, reflect offmirror 274, pass through semitransparent mirror 273 through opticsubsystem 268 and onto optical sensitive surface 266. Many otherconfigurations are possible. The transmission of the radiation iscontrolled by optical shutter 270 via controller 275. Similarly, thelight that reaches the imager 266 is controlled by controller 275 andoptical shutter 269. These optical shutters 269, 270 can be liquidcrystal devices, Kerr or Pockel cells, garnet films, other spatial lightmonitors or, preferably, high speed optical shutters such as describedin patents and patent applications of the 3DV Systems Ltd., of Yokneam,Israel, as set forth above or equivalent. Since much of the technologyused in this invention related to the camera and shutter system isdisclosed in the 3DV patents and patent applications, it will not berepeated here, by is incorporated by reference herein.

In some embodiments, it may be important to assure that the lens throughwhich the laser radar radiation passes is clean. As a minimum, adiagnostic system is required to inform the RtZF™ or other system thatthe lens are soiled and therefore the laser radar system can not berelied upon. Additionally, in some applications, means are provided toclean one or more of the lens or to remove the soiled surface. In thelatter case, a roll of thin film can be provided which, upon thedetection of a spoiled lens, rolls up a portion of the film and therebyprovides a new clean surface. When the roll is used up it can bereplaced. Other systems provide one or more cleaning methods such as asmall wiper or the laser radar unit can move the lens into a cleaningstation. Many other methods are of course possible and the inventionhere is basically concerned with ascertaining that the lens is clean andif not informing the system of this fact and, in some cases, cleaning orremoving the soiled surface.

Note that although laser radar and radar have been discussed separately,in some implementations, it is desirable to use both a radar system anda laser radar system. Such a case can be where the laser radar system isnot capable to achieve sufficient range in adverse weather whereas theradar has the requisite range but insufficient resolution. The radarunit can provide a warning that a potentially dangerous situation existsand thus the vehicle speed should be reduced until the laser radardevice and obtain an image with sufficient resolution to permit anassessment of the extent of the danger and determine whether appropriateactions should be undertaken.

5.6 Antennas

When the interrogation system makes use of radar such as systems in useat 24 GHz and 77 GHz, a key design issue is the antenna. The inventionsherein contemplate the use of various types of antennas such as dipoleand monopole designs, yagi, steerable designs such as solid state phasedarray and so called smart antennas. All combinations of antennas forradar surveillance around a vehicle are within the scope if theinventions disclosed herein. In particular, the Rotman lens offerssignificant advantages as disclosed in L. Hall, H. Hansen and D. Abbott“Rotman lens for mm-wavelengths”, Smart Structures, Devices, andSystems, SPIE Vol. 4935 (2002). Other antenna designs can be applicable.In some cases, one radar source can be used with multiple antennas.

6. Smart Highways

The theme of the inventions disclosed herein is that automobileaccidents can be eliminated and congestion substantially mitigatedthrough the implementation thereof. After sufficient implementationshave occurred, the concept of a smart highway becomes feasible. When asignificant number of vehicles have the capability of operating in asemi-autonomous manner, then dedicated highway lanes (like the HOV lanesnow in use) can be established where use of the lanes is restricted toproperly equipped vehicles. Vehicles operating on these lanes can travelin close packed high speed formations since each of them will know thelocation of the road, their location on the road and the location ofevery other vehicle in such a lane. Accidents on these lanes will notoccur and the maximum utilization of the roadway infrastructure willhave been obtained. Vehicle owners will be highly motivated to ownequipped vehicles since their travel times will be significantly reducedand while traveling on such lanes, control of the vehicle can beaccomplished by the system and they are then free to talk on thetelephone, read or whatever.

7. Weather and Road Condition Monitoring

The monitoring of the weather conditions and the control of the vehicleconsistent with those conditions has been discussed herein. Themonitoring of the road conditions and in particular icing has also beendiscussed elsewhere herein and in other patents and patent applicationsof the current assignee. Briefly, a vehicle will be controlled so as toeliminate accidents under all weather and road conditions. This in somecases will mean that the vehicle velocity will be controlled and, insome cases, travel will be prohibited until conditions improve.

8. Communication with Other Vehicles—Collision Avoidance

8.1 Requirements

MIR might also be used for vehicle-to-vehicle communication except thatit is line of sight. An advantage is that we can know when a particularvehicle will respond by range gating. Also, the short time oftransmission permits many vehicles to communicate at the same time. Thepreferred system is to use spread spectrum carrier-less coded channels.

One problem which will require addressing as the system becomes matureis temporary blockage of a satellite by large trucks or other movableobjects whose location cannot be foreseen by the system designers.Another concern is to prevent vehicle owners from placing items on thevehicle exterior that block the GPS and communication antennas.

The first problem can be resolved if the host vehicle can communicatewith the blocking trucks and can also determine its relative location,perhaps through using the vehicle exterior monitoring system. Then thecommunication link will provide the location of the adjacent truck andthe monitoring system will provide the relative location and thus theabsolute location of the host vehicle can be determined.

The communication between vehicles for collision avoidance purposescannot solely be based on line-of-sight technologies as this is notsufficient since vehicles which are out of sight can still causeaccidents. On the other hand, vehicles that are a mile away from oneanother but still in sight, need not be part of the communication systemfor collision avoidance purposes. Messages sent by each vehicle, inaccordance with an embodiment of the invention, can contain informationindicating exactly where it is located and perhaps information as towhat type of vehicle it is. The type of vehicle can include emergencyvehicles, construction vehicles, trucks classified by size and weight,automobiles, and oversized vehicles. The subject vehicle can thereforeeliminate all vehicles that are not potential threats, even if suchvehicles are very close, but on the other side of the highway barrier.

The use of a wireless Ethernet protocol can satisfy the needs of thenetwork, consisting of all threatening vehicles in the vicinity of thesubject vehicle. Alternately, a network where the subject vehicletransmits a message to a particular vehicle and waits for a responsecould be used. From the response time, assuming that the clocks of bothvehicles are or can be synchronized, the relative position of othervehicles can be ascertained which provides one more method of positiondetermination. Thus, the more vehicles that are on the road with theequipped system, the greater accuracy of the overall system and thesafer the system becomes.

To prevent accidents caused by a vehicle leaving the road surface andimpacting a roadside obstacle requires only an accurate knowledge of theposition of the vehicle and the road boundaries. To prevent collisionswith other vehicles requires that the position of all nearby automobilesmust be updated continuously. Just knowing the position of a threateningvehicle is insufficient. The velocity, size and/or orientation of thevehicle are also important in determining what defensive action orreaction may be required. Once all vehicles are equipped with the systemof this invention, the communication of all relevant information willtake place via a communication link, e.g., a radio link. In addition tosignaling its absolute position, each vehicle will send a messageidentifying the approximate mass, velocity, orientation, and/or otherrelevant information. This has the added benefit that emergency vehiclescan make themselves known to all vehicles in their vicinity and all suchvehicles can then take appropriate action to allow passage of theemergency vehicle. The same system can also be used to relay accident orother hazard information from vehicle to vehicle through an ad-hoc ormesh network.

8.2 A Preferred System

One preferred method of communication between vehicles uses that portionof the electromagnetic spectrum that permits only line of sightcommunication. In this manner, only those vehicles that are in view cancommunicate. In most cases, a collision can only occur between vehiclesthat can see each other. This system has the advantage that the“communications network” only contains nearby vehicles. This wouldrequire that when a truck, for example, blocks another stalled vehiclethat the information from the stalled vehicle be transmitted via thetruck to a following vehicle. An improvement in this system would use arotating aperture that would only allow communication from a limitedangle at a time further reducing the chance for multiple messages tointerfere with each other. Each vehicle transmits at all angles butreceives at only one angle at a time. This has the additional advantageof confirming at least the direction of the transmitting vehicle. Aninfrared rotating receiver can be looked at as similar to the human eye.That is, it is sensitive to radiation from a range of directions andthen focuses in on the particular direction, one at a time, from whichthe radiation is coming. It does not have to scan continuously. In fact,the same transmitter which transmits 360 degrees could also receive from360 degrees with the scanning accomplished using software.

An alternate preferred method is to use short distance radiocommunication so that a vehicle can receive position information fromall nearby vehicles such as the DS/SS system. The location informationreceived from each vehicle can then be used to eliminate it from furthermonitoring if it is found to be on a different roadway or not in apotential path of the subject vehicle.

Many communications schemes have been proposed for inter-vehicle andvehicle-to-road communication. At this time, a suggested approachutilizes DS/SS communications in the 2.4 GHz INS band. Experiments haveshown that communications are 100 percent accurate at distances up to200 meters. At a closing velocity of 200 KPH, at 0.5 g deceleration, itrequires 30 meters for a vehicle to stop. Thus, communications accurateto 200 meters is sufficient to cover all vehicles that are threateningto a particular vehicle.

A related method would be to use a MIR system in a communications mode.Since the width of the pulses typically used by MIR is less than ananosecond, many vehicles can transmit simultaneously without fear ofinterference. Other spread spectrum methods based on ultra wideband ornoise radar are also applicable. In particular, as discussed below, acommunication system based on correlation of pseudorandom or other codesis preferred.

With either system, other than the MIR system, the potential exists thatmore than one vehicle will attempt to send a communication at the sametime and there will then be a ‘data collision’. If all of thecommunicating vehicles are considered as being part of a local areanetwork, the standard Ethernet protocol can be used to solve thisproblem. In that protocol, when a data collision occurs, each of thetransmitting vehicles which was transmitting at the time of the datacollision would be notified that a data collision had occurred and thatthey should retransmit their message at a random time later. Whenseveral vehicles are in the vicinity and there is the possibility ofcollisions of the data, each vehicle can retain the coordinates lastreceived from the surrounding vehicles as well as their velocities andpredict their new locations even though some data was lost.

If a line of sight system is used, an infrared, terahertz or MIR systemwould be good choices. In the infrared case, and if an infrared systemwere also used to interrogate the environment for non-equipped vehicles,pedestrians, animals etc., as discussed below, both systems could usesome of the same hardware.

If point-to-point communication can be established between vehicles,such as described in U.S. Pat. No. 5,528,391 to Elrod, then the need fora collision detection system like Ethernet would not be required. If thereceiver on a vehicle, for example, only has to listen to one senderfrom one other vehicle at a time, then the bandwidth can be considerablyhigher since there will not be any interruption.

When two vehicles are communicating their positions to each other, it ispossible through the use of range gating or the sending of a “clear tosend signal” and timing the response to determine the separation of thevehicles. This assumes that the properties of the path between thevehicles are known which would be the case if the vehicles are withinview of each other. If, on the other hand, there is a row of trees, forexample, between the two vehicles, a false distance measurement would beobtained if the radio waves pass through a tree. If the communicationfrequency is low enough that it can pass through a tree in the aboveexample, it will be delayed. If it is a much higher frequency such thatis blocked by the tree, then it still might reach the second vehiclethrough a multi-path. Thus, in both cases, an undetectable range errorresults. If a range of frequencies is sent, as in a spread spectrumpulse, and the first arriving pulse contains all of the sentfrequencies, then it is likely that the two vehicles are in view of eachother and the range calculation is accurate. If any of the frequenciesare delayed, then the range calculation can be considered inaccurate andshould be ignored. Once again, for range purposes, the results of manytransmissions and receptions can be used to improve the separationdistance accuracy calculation. Alternate methods for determining rangecan make use of radar reflections, RFID tags etc.

8.3 Enhancements

In the accident avoidance system of the present invention, theinformation indicative of a collision could come from a vehicle that isquite far away from the closest vehicles to the subject vehicle. This isa substantial improvement over the prior art collision avoidancesystems, which can only react to a few vehicles in the immediatevicinity. The system described herein also permits better simultaneoustracking of several vehicles. For example, if there is a pileup ofvehicles down the highway, then this information can be transmitted tocontrol other vehicles that are still a significant distance from theaccident. This case cannot be handled by prior art systems. Thus, thesystem described here has the potential to be used with the system ofthe U.S. Pat. No. 5,572,428 to Ishida, for example.

The network analogy can be extended if each vehicle receives andretransmits all received data as a single block of data. In this way,each vehicle is assured in getting all of the relevant information evenif it gets it from many sources. Even with many vehicles, the amount ofdata being transmitted is small relative to the bandwidth of theinfrared optical or radio technologies. In some cases, a receiver andre-transmitter can be part of the highway infrastructure. Such a casemight be on a hairpin curve in the mountains where the oncoming trafficis not visible.

In some cases, it may be necessary for one vehicle to communicate withanother to determine which evasive action each should take. This couldoccur in a multiple vehicle situation when one car has gone out ofcontrol due to a tire failure, for example. In such cases, one vehiclemay have to tell the other vehicle what evasive actions it is planning.The other vehicle can then calculate whether it can avoid a collisionbased on the planned evasive action of the first vehicle and if not, itcan inform the first vehicle that it must change its evasive plans. Theother vehicle would also inform the first vehicle as to what evasiveaction it is planning. Several vehicles communicating in this manner candetermine the best paths for all vehicles to take to minimize the dangerto all vehicles.

If a vehicle is stuck in a corridor and wishes to change lanes in heavytraffic, the operator's intention can be signaled by the operatoractivating the turn signal. This could send a message to other vehiclesto slow down and let the signaling vehicle change lanes. This would beparticularly helpful in an alternate merge situation and have asignificant congestion reduction effect.

8.4 Position-Based Code Communication

In conventional wireless communication such as between cell phones and acell phone station or computers in a local area network, a limitednumber of clients are provided dedicated channels of communication witha central server. The number of channels is generally limited and thedata transfer rate is maximized. The situation of communication betweenvehicles (cars, trucks, buses, boats, ships, airplanes) is different inthat devices are all peers and the communication generally depends ontheir proximity. In general, there is no central server and each vehiclemust be able to communicate with each other vehicle without goingthrough a standard server.

Another distinguishing feature is that there may be a large number ofvehicles that can potentially communicate with a particular vehicle.Thus, there needs to be a large number of potential channels ofcommunication. One method of accomplishing this is based on the conceptof noise radar as developed by Lukin et al. and described in thefollowing (all of which are incorporated by reference herein):

1. K. A. Lukin. Noise Radar Technology for Short Range Applications,Proc of the. 5th Int. Conference and Exhibition on Radar Systems,(RADAR'99), May 17–21, Brest, France, 1999, 6 pages;

2. K. A. Lukin. Advanced Noise Radar Technology. Proc. of the PIERSWorkshop on Advances in Radar Methods. Apr. 20–22, 1998, Hotel Dino,Baveno, Italy, JRC-Ispra 1998, pp. 137–140;

3. W. Keydel and K. Lukin. Summary of Discussion in working Group V:Unconventional New Techniques and Technologies for Future Radar, Proc.of the PIERS Workshop in Radar Methods. Apr. 20–22, 1998, Hotel Dino,Baveno, Italy, 1998, pp. 28–30;

4. Lukin K. A., Hilda A. Cerdeira and Colavita A. A. Chaotic instabilityof currents in reverse biased multilayered structure. Appl. PhysicsLetter, v. 77(17), 27 Oct. 1997, pp. 2484–2496;

5. K. A. Lukin. Noise Radar Technology for Civil Application. Proc. ofthe 1 st EMSL User Workshop. 23–24 Apr. 1996, JRC-Ispra, Italy, 1997,pp. 105–112;

6. A. A. Mogyla. Adaptive signal filtration based on the two-parametricrepresentation of random processes. Collective Volume of IRE NASU, Vol.2, No. 2 pp. 137–141, 1997, (in Russian);

7. A. A. Mogyla, K. A. Lukin. Two-Parameter Representation ofNon-Stationary Random Signals with a Finite Weighted Average Value ofEnergy. The Collective Volume of IRE NASU, No. 1, pp. 118–124, 1996, (inRussian);

8. K. A. Lukin. Noise Radar with Correlation Receiver as the Basis ofCar Collision Avoidance System. 25th European Microwave Conference,Bologna; Conference Proceedings, UK, Nexus, 1995, pp. 506–507, 1995;

9. K. A. Lukin, V. A. Rakityansky. Dynamic chaos in microwaveoscillators and its applications for Noise Radar development, Proc. 3rdExperimental Chaos Conference, Edinburg, Scotland, UK, 21–23 Aug., 1995;

10. V. A. Rakityansky, K. A. Lukin. Excitation of the chaoticoscillations in millimeter BWO, International Journal of Infrared andMillimeter Waves, vol. 16, No. 6, June, pp. 1037–1050, 1995;

11. K. A. Lukin. Ka-band Noise Radar. Proc. of the Millimeter andSubmillimeter Waves, Jun. 7–10 1994, Kharkov, Ukraine; Vol. 2, pp.322–324, 1994;

12. K. A. Lukin, Y. A. Alexandrov, V. V. Kulik, A. A. Mogila, V. A.Rakityansky. Broadband millimeter noise radar, Proc. Int. Conf on ModernRadars, Kiev, Ukraine, pp. 30–31, 1994 (in Russian);

13. K. A. Lukin. High-frequency chaotic oscillations from Chua'scircuit. Journal of Circuits, Systems, and Computers, Vol. 3, No. 2,June 1993, pp. 627–643; In the book: Chua's Circuit Paradigma for Chaos,World Scientific, Singapore, 1993;

14. K. A. Lukin, V. A. Rakityansky. Application of BWO for excitation ofthe intensive chaotic oscillations of millimeter wave band. 23-rdEuropean Microwave Conference. September 6–9, Madrid, Spain. Conf.Proceed. pp. 798–799, 1993;

15. K. A. Lukin, V. A. Rakityansky. Excitation of intensive chaoticoscillations of millimetre wave band. Proc. of ISSSE, Paris, September1–4, pp. 454–457, 1992;

16. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Non-CoherentReflectometry Method for Measurement of Plasma Cut-Off Layer Position,Proc. of the Int. Conference on Millimeter Wave and Far-Infrared.Technology, Beijing, China, 17–21 Aug., 1992;

17. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Autodyne effect in BWOwith chaotic dynamic. Collective Volume of IRE NASU, pp. 95–100, 1992,(in Russian);

18. V. V. Kulik, K. A. Lukin, V. A. Rakityansky. Application ofnoncoherent reflectometry method for fusion plasma dyagnostic.Collective Volume of IRE NASU, pp. 13–18, 1992, (in Russian);

19. B. P. Efimov, K. A. Lukin, V. A. Rakityansky. Chaotic interaction ofmodes in the electron-wave auto-oscillator with two feedback channels,Letters in Journal of Technical Physics, v. 15, No. 18, pp. 9–12, 1989,(in Russian);

20. B. P. Efimov, K. A. Lukin, V. A. Rakityansky. Transformation ofchaotic oscillation power spectrum by reflections. Journal of TechnicalPhysics, vol. 58, No. 12, pp. 2388–2400, 1988 (in Russian)).

The concept of noise radar is discussed in detail in the Lukinreferences listed above. A description of noise radar is includedelsewhere herein and the discussion here will be limited to the use ofpseudo random noise in a spread spectrum or Ultra-wideband spectrumenvironment for communication purposes.

Generally, a particular segment or band of the electromagnetic spectrumwhich is compatible with FCC regulations will be selected forvehicle-to-vehicle communication purposes. Such a band could include,for example 5.9 GHz to 5.91 GHz. The noise communication device willtherefore transmit information in that band. Each vehicle will transmita pseudorandom noise signal in a carrier-less fashion composed offrequencies within the chosen band. The particular code transmitted by aparticular vehicle should be unique. Generally, the vehicle willtransmit its code repetitively with a variable or fixed spacing betweentransmissions. The information which the vehicle wishes to transmit isencoded using the vehicle's code by any of a number of differenttechniques including phase modulation of distance or time between codetransmissions, phase or amplitude modulation of the code sequencesthemselves, changes of the polarity of the entire code sequence or theindividual code segments, or bandwidth modulation of the code sequence.Other coding technologies would also applicable and this invention isnot limited to any particular coding method.

For example, a vehicle can have a 64 bit code which is a combination ofa vehicle identification number and the GPS coordinates of the vehiclelocation. The vehicle would continuously transmit this 64 bit code usingfrequencies within the selected band. The 64 bit code could include bothpositive and negative bits in addition to 0 bits. When identifying thevehicle, the receiver could rectify the bits resulting in a 64 bit codeof 0's and 1's. The information which the transmitting vehicle wishes tosend could be represented by the choice of polarity of each of the codebits.

Once a particular vehicle begins communicating with another particularvehicle, the communication channel must remain intact until the entiremessage has been transmitted. Since there may be as many as 100 to 1000vehicles simultaneously transmitting within radio range of the receivingvehicle, a transmitting vehicle must have a code which can be known tothe receiving vehicle. One preferred technique is to make thisidentification code a function of the GPS coordinate location oftransmitting vehicle. The code would need to be coarse enough so thatinformation to be transmitted by the transmitting vehicle isaccomplished before the transmitting vehicle changes its identification.If this information includes a position and velocity of the transmittingvehicle, then the receiving vehicle can determine the new transmittingcode of the transmitting vehicle.

For example, the transmitting vehicle determines its location within onemeter. It is unlikely that any other vehicle will be located within thesame meter as the transmitting vehicle. Thus, the transmitting vehiclewill have a unique code which it can send as a pseudorandom sequence inthe noise communication system. A nearby vehicle can search allinformation received by its antenna for a sequence which represents eachspace within 30 meters of the receiving vehicle. If it detects such asequence, it will know that there are one or more vehicles within 30meters of the receiving vehicle. The search can now be refined to locatevehicles based on their direction since again the receiving vehicle cancalculate the sequences that would be transmitted from a vehicle fromany particular location within the 30 meter range. Once a particularvehicle has been identified, the receiving vehicle can begin to receiveinformation from the transmitting vehicle through one or more of thecoding schemes listed above. Since the information will preferablycontain at least the velocity of transmitting vehicle, the receivingvehicle can predict any code sequence changes that take place and thusmaintain communication with a particular vehicle even as the vehicle'scode changes due to its changing position. The information beingtransmitted can also contain additional information about the vehicleand/or its occupants.

In this manner, a receiving vehicle can selectively receive informationfrom any vehicle within its listenable range. Such range may be limitedto 100 meters for a highly congested area or extend to 5000 meters in arural environment. In this manner, each vehicle becomes a node on thetemporary local area network and is only identified by its GPS location.Any vehicle can communicate with any other vehicle and when manyvehicles are present, a priority scheme can be developed based on theurgency of the message, the proximity of vehicle, the possibility of acollision, or other desired prioritizing scheme.

The code transmitted by a particular vehicle will begin with a sequencethat indicates, for example, the largest GPS segment that locates thevehicle which may be a segment 100 km square, for example. The next bitsin the sequence would indicate which of next lower subsections which,for example, could be 10 km square. The next set of bits could furtherrefine this to a 1 km square area and so on down to the particularsquare meter where the vehicle is located. Other units, such as angles,degrees, minutes, seconds etc., could be more appropriate for locating avehicle on the surface of spherical earth. By using this scheme, areceiving vehicle can search for all vehicles located within its 1 km orsquare segment and then when a vehicle is found, the search can becontinuously refined until the exact location of the transmittingvehicle has been determined. This is done through correlation. The 100or so vehicles transmitting with a range would all transmit low levelsignals which would appear as noise to the receiving vehicle. Thereceiving vehicle would need to know the code a particular vehicle wastransmitting before it could identify whether that code was present inthe noise. The code derived by the vehicle to be transmitted must besufficiently unique that only one vehicle can have a particular code ata particular time. Since the messages from different vehicles areseparated through correlation functions, all vehicles must have uniquetransmission codes which are not known beforehand by the receivingvehicle yet must be derivable by the receiving vehicle.

The communication need not be limited to communication between movingvehicles. This same technology permits communication between a vehicleand an infrastructure-based station.

There is no limit to the types of information that can be exchangedbetween vehicles or between vehicles and infrastructure-based stations.For example, if an event occurs such as an accident or avalanche, roaderosion, fallen tree, or other event which temporarily changes theability to travel safely on a section of a lane on a highway, anauthorized agent can place the transmitting sign near the affectedsection of roadway which would transmit information using the noisecommunication technique to all oncoming vehicles within a 1 km range,for example. Prior to the placement of such a sign, a police vehiclecould transmit a similar message to adjacent vehicles. Even an ordinarydriver who first appears on the scene and identifies a potential hazardcan send this message to vehicles within range of the hazard and can tagthis message as a high priority message. An infrastructure-basedreceiving station can receive such a message and notify the emergencycrews that attention is immediately required at a particular location onthe highway. In this manner, all vehicles that could be affected by suchan event as well as urgency response organizations can be immediatelynotified as soon as a hazard, such as an accident, occurs therebygreatly reducing the response time and minimizing the chance of vehiclesengaging the hazardous location.

If a vehicle passes through a precise positioning location as describedelsewhere herein, that vehicle (the vehicle's processor or computer)momentarily knows or can calculate the errors in the GPS signals andthus becomes a differential correction station. The error correctionscan then be transmitted to nearby vehicles plus enhancing theirknowledge of their position. If the PPS vehicle also has an onboardaccurate clock, then the carrier phase of the satellite signals at thePPS location can be predicted and thus, as the vehicle leaves the PPSstation, it can operate on carrier phase RTK differential GPS and thusknow its position within centimeters or less. Similarly, if the phase ofthe carrier waves at PPS station is transmitted to adjacent vehicles,each vehicle also can operate on RTK carrier phase differential GPS.Thus, as many cars pass the PPS the accuracy with which each vehicleknows its position is continuously upgraded and at the time when thelikelihood of collision between vehicles is a maximum, that is when manyvehicles are traveling on a roadway, the accuracy with which eachvehicle knows its location is also maximized. The RtZF™ systemautomatically improves as the danger of collision increases.

Other information which a vehicle can transmit relates to the GPSsignals that it is receiving. In this manner, another form ofdifferential GPS can occur called relative differential GPS. Withoutnecessarily improving the accuracy with which a given vehicle preciselyknows its position, by comparing GPS signals from one vehicle toanother, the relative location of two vehicles can again be veryaccurately determined within centimeters. This of course is particularlyimportant for collision avoidance.

Other information that can be readily transmitted either from vehicle tovehicle or from infrastructure-based stations to vehicles includes anyrecent map updates. Since a vehicle will generally always be listening,whenever a map update occurs this information can be received by avehicle provided it is within range of a transmitter. This could occurovernight while the vehicle is in the garage, for example. Each vehiclewould have a characteristic time indicating the freshness of theinformation in its local map database. As the vehicle travels andcommunicates with other vehicles, this date can be readily exchanged andif a particular vehicle has a later map version than the other vehicle,it would signal the first vehicle requesting that the differencesbetween the two map databases be transmitted from the first to thesecond vehicle. This transmission can also occur between aninfrastructure-based station and a vehicle. Satellites, cell phonetowers, etc. can also be used for map updating purposes.

If the operator of a particular vehicle wishes to send a text or voicemessage to another identified vehicle, this information can also be sentthrough the vehicle-to-vehicle communication system described herein.Similarly, interaction with the Internet via an infrastructure-basedstation can also be accomplished. In some cases, it may be desirable toaccess the Internet using communication channels with other vehicles.Perhaps, one vehicle has the satellite, Wi-Fi, Wimax or other link tothe Internet while a second vehicle does not. The second vehicle couldstill communicate with the Internet through the first Internet-enabledvehicle.

Through the communication system based on noise or pseudonoisecommunication as described above is ubiquitous, the number of pathsthrough which information can be transmitted to and from a vehicle issubstantially increased which also greatly increases the reliability ofthe system since multiple failures can occur without affecting theoverall system operation. Thus, once again the goal of zero fatalities™is approached through this use of vehicle-to-vehicle communication.

By opening this new paradigm for communication between vehicles, andthrough the use of message relay from one vehicle to another, occupantsof one vehicle can communicate with any other vehicle on a road.Similarly, through listening to infrastructure-based stations, theoccupants can communicate with non-vehicle occupants. In many ways, thissystem supplements the cell phone system but is organized under totallydifferent principles. In this case, the communication takes placewithout central stations or servers. Although servers and centralstations can be attached to the system, the fundamental structure is oneof independent nodes and temporary connections based on geographicproximity.

The system is self limiting in that the more vehicles communicating, thehigher the noise level and the more difficult it will be to separatemore distant transmitters. When a vehicle is traveling in a ruralenvironment, for example, where there are few sparsely locatedtransmitters, the noise level will be low and communication with moredistant vehicles facilitated. On the other hand, during rush hour, therewill be many vehicles simultaneously communicating thus raising thenoise level and limiting the ability of a receiver to receive distanttransmissions. Thus, the system is automatically adjusting.

There are several collision avoidance-based radar systems beingimplemented on vehicles on the highways today. The prominent systemsinclude ForeWarn™ by Delco division of the Delphi Corporation and theEaton Vorad systems. These systems are acceptable as long as fewvehicles on the roads have such system. As the number of radar-equippedvehicles increases, the reliability of each system decreases as radartransmissions are received that originate from other vehicles. Thisproblem can be solved through the use of noise radar as described in thevarious technical papers by Lukin et al. listed above.

Noise radar typically operates in a limited band of frequenciessimilarly to spread spectrum technologies. Whereas spread spectrumutilizes a form of carrier frequency modulation, noise radar does not.It is carrier-less. Typically, a noise-generating device is incorporatedinto the radar transmitter such that the signal transmitted appears asnoise to any receiver. A portion of the noise signal is captured as itis transmitted and fed to a delay line for later use in establishing acorrelation with a reflected pulse. In the manner described in the Lukinet al. papers, the distance and velocity of a reflecting object relativeto the transmitter can be readily determined and yet be detectable byany other receiver. Thus, a noise radar collision avoidance system suchas discussed in U.S. Pat. No. 6,121,915, U.S. Pat. No. 5,291,202, U.S.Pat. No. 5,719,579, and U.S. Pat. No. 5,075,863 becomes feasible. Lukinet al. first disclosed this technology in the above-referenced papers.

Although noise radar itself is not new, the utilization of noise radarfor the precise positioning system described herein is not believed tohave been previously disclosed by others. Similarly, the use of noiseradar for detecting the presence of an occupant within a vehicle or ofany object within a particular range of a vehicle is also not believedto have been previously disclosed by others. By setting the correlationinterval, any penetration or motion of an object within that intervalcan be positively detected. Thus, if interval is sent at 2 meters, forexample, the entire interior of a vehicle can be monitored with onesimple device. If any object is moving within the vehicle, then this canreadily detected. Similarly, the space being monitored can be limited toa portion of the interior of the vehicle such as the right passengerseat or the entire rear seat. In this manner, the presence of any movingobject within that space can be determined and thus problems such as ahiding assailant or a child or animal left in a parked car can beaddressed. A device placed in the trunk can monitor the motion of anyobject that has been trapped within the trunk thereby eliminating thatwell-known problem.

The radar system to be used for the precise positioning system can alsobe used for monitoring the space around a vehicle. In this case, asimple structure involving the placement of four antennas on the vehicleroof, for example, can be used to locate and determine the velocity ofany object approaching or in the vicinity of the vehicle. Using neuralnetworks and the reflection received from the four antennas, thelocation and velocity of an object can be determined and by observingthe signature using pattern recognition techniques such as neuralnetworks, the object can be identified. Each antenna would send andreceive noise radar waves from an angle of, for example, 180 degrees.One forward and one rear antenna could monitor the left side of thevehicle and one forward and one rear antenna could monitor the rightside. Similarly, the two rear antennas could monitor the rear of thevehicle and the two forward antennas could monitor the forward part ofthe vehicle. In this manner, one simple system provides rear impactanticipatory sensing, automatic cruise control, forward impactanticipatory sensing, blind spot detection, and side impact anticipatorysensing. Since the duty cycle of the precise positioning system issmall, most of the time would be available for monitoring the spacesurrounding the vehicle. Through the choice of the correlation intervaland coding scheme (CDMA, noise, etc.), the distance monitored can alsobe controlled.

In addition to the position-based code, an ID related to the type ofvehicle could also be part of the code so that an interested vehicle mayonly wish to interrogate vehicles of a certain class such as emergencyvehicles. Also having information about the vehicle type communicated tothe host vehicle can quickly give an indication of the mass of theoncoming vehicle which, for example, could aid an anticipatory sensor inprojecting the severity of an impending crash.

Although it has been generally assumed that vehicle-to-vehiclecommunication will take place through a direct link or through an ad-hocor mesh network, when Internet access becomes ubiquitous for vehicles,this communication could also take place via the Internet through aWi-Fi or Wimax or equivalent link. Additionally, the use of an ad-hoc ormesh network for vehicle-to-vehicle communication especially to sending:relative location, velocity and vehicle mass information for collisionavoidance purposes; GPS, DGPS, PPS related information for locationdetermination and error correction purposes; traffic congestion or roadcondition information; weather or weather related information; and,vehicle type information particularly for emergency vehicleidentification so that the host vehicle can take appropriate actions toallow freedom of passage for the emergency vehicle, are consideredimportant parts of the present inventions. In fact, a mesh or ad-hocnetwork can greatly improve the working of an ubiquitous WI-FI, Wimax orequivalent Internet system thereby extending the range of the wirelessInternet system.

This system also supports emergency vehicles sending warnings tovehicles that are in its path since it, and only it, will know its routefrom its present location to its destination. Such a system will permitsignificant advanced warning to vehicles on the route and also allow forthe control of traffic lights based on its planned route long before itarrives at the lights. In this regard, see “Private Inventor FilesPatent Application For Telematics-Based Public and Emergency FirstResponders Safety Advisory System”, ITS America News Release Feb. 13,2004, for a discussion of a primitive but similar system.

An alternate approach to using the code based on location system is touse a vehicle ID system in connection with an easily accessible centraldatabase that relates the vehicle ID to its location. Then communicationcan take place via a code based in the vehicle ID, or some equivalentmethod.

9. Infrastructure-to-Vehicle Communication

Initial maps showing roadway lane and boundary location for the CONUScan be installed within the vehicle at the time of manufacture. Thevehicle thereafter would check on a section-by-section basis whether ithad the latest update information for the particular and surroundinglocations where it is being operated. One method of verifying thisinformation would be achieved if a satellite or Internet connectionperiodically broadcasts the latest date and time or version that eachsegment had been most recently updated. This matrix would amount to asmall transmission requiring perhaps a few seconds of airtime. Anyadditional emergency information could also be broadcast in between theperiodic transmissions to cover accidents, trees falling onto roads etc.If the periodic transmission were to occur every five minutes and if themotion of a vehicle were somewhat restricted until it had received aperiodic transmission, the safety of the system can be assured. If thevehicle finds that it does not have the latest map information,vehicle-to-vehicle communication, vehicle-to-infrastructurecommunication, Internet communication (Wi-Fi, Wi-max or equivalent), orthe cell phone in the vehicle can be used to log onto the Internet, forexample, and the missing data downloaded. An alternate is for the GEOs,LEOs, or other satellites, to broadcast the map corrections directly.

It is also possible that the map data could be off-loaded from atransmitter on the highway itself or at a gas station, for example, asdiscussed above. In that manner, the vehicles would only obtain that mapinformation which is needed and the map information would always be upto the minute. As a minimum, temporary data communication stations canbe placed before highway sections that are undergoing construction orwhere a recent blockage has occurred, as discussed above, and where themaps have not yet been updated. Such an emergency data transfer would besignaled to all approaching vehicles to reduce speed and travel withcare. Such information could also contain maximum and minimum speedinformation which would limit the velocity of vehicles in the area.

There is other information that would be particularly useful to avehicle operator or control system, including in particular, the weatherconditions, especially at the road surface. Such information could beobtained by road sensors and then transmitted to all vehicles in thearea by a permanently installed system as disclosed above and in thecurrent assignee's U.S. Pat. No. 6,662,642. Alternately, there have beenrecent studies that show that icing conditions on road surfaces, forexample, can be accurately predicted by local meteorological stationsand broadcast to vehicles in the area. If such a system is not present,then the best place to measure road friction is at the road surface andnot on the vehicle. The vehicle requires advance information of an icingcondition in order to have time to adjust its speed or take otherevasive action. The same road-based or local meteorological transmittersystem could be used to warn the operators of traffic conditions,construction delays etc. and to set the local speed limit. Once onevehicle in an area has discovered an icing condition, for example, thisinformation can be immediately transmitted to all equipped vehiclesthrough the vehicle-to-vehicle communication system discussed above.

A number of forms of infrastructure-to-vehicle communication have beendiscussed elsewhere herein. These include map and differential GPSupdating methods involving infrastructure stations which may be locatedat gas stations, for example. Also communications with precisepositioning stations for GPS independent location determination havebeen discussed. Communications via the Internet using either satelliteInternet services with electronic steerable antennas such as areavailable from KVH, Wi-Fi or Wimax which will undoubtedly becomeavailable ubiquitously throughout the CONUS, for example. All of theservices that are now available on the Internet plus may new serviceswill thus be available to vehicle operators and passengers. The updatingof vehicle resident software will also become automatic via such links.The reporting of actual (diagnostics) and forecasted (prognostics)vehicle failures will also able to be communicated via one of theselinks to the authorities, the smart highway monitoring system, vehicledealers and manufacturers (see U.S. patent application Ser. No.10/701,361, now U.S. Pat. No. 6,988,026). This application along withthe inventions herein provide a method of notifying interested partiesof the failure or forecasted failure of a vehicle component using avehicle-to-infrastructure communication system. Such interested partiescan include, but are not limited to: a vehicle manufacturer so thatearly failures on a new vehicle model can be discovered so as to permitan early correction of the problem; a dealer so that it can schedulefixing of the problem so as to provide for the minimum inconvenience oftheir customer and even, in some cases, dispatching a service vehicle tothe location of the troubled vehicle; NHTSA so that they can trackproblems (such as for Firestone tire problem) before they become anational issue; the police, EMS, fire department and other emergencyservices so that they can prepare for a potential emergency etc. Forexample in “Release of Auto Safety Data Is Disputed”, New York TimesDec. 13, 2002 it is written “After Firestone tire failures on FordExplorers led to a national outcry over vehicle safety, Congress ordereda watchdog agency to create an early-warning system for automotivedefects that could kill or injure people.” The existence of the systemdisclosed herein would provide an automatic method for such a watchdoggroup to monitor all equipped vehicles on the nation's highways. As apreliminary solution, it is certainly within the state of the art todayto require all vehicles to have an emergency locator beacon orequivalent that is impendent of the vehicle's electrical system and isactivated on a crash, rollover or similar event.

Although the '361 application primarily discusses diagnostic informationfor the purpose of reporting present or forecasted vehicle failures,there is of course a wealth of additional data that is available on avehicle related to the vehicle operation, its location, its history etc.where an interested party may desire that such data be transferred to asite remote from the vehicle. Interested parties could include theauthorities, parents, marketing organizations, the vehicle manufacturer,the vehicle dealer, stores or companies that may be in the vicinity ofthe vehicle, etc. There can be significant privacy concerns here whichhave not yet been addressed. Nevertheless, with the proper safeguardsthe capability described herein is enabled partially by the teachings ofthis invention.

For critical functions where a software-induced system failure cannot betolerated, even the processing may occur on the network achieving whatpundits have been forecasting for years that “the network is thecomputer”. Vehicle operators will also have all of the functions nowprovided by specialty products such as PDAs, the Blackberry, cell phonesetc. available as part of the infrastructure-to-vehicle communicationsystems disclosed herein.

There are of course many methods of transferring data wirelessly inaddition to the CDMA system described above. Methods using ultrawideband signals were first disclosed by the current assignee inprevious patents and are reinforced here. Much depends of the will ofthe FCC as to what method will eventually prevail. Ultra wideband withinthe frequency limits set by the FCC is certainly a prime candidate andlends itself to the type of CDMA system where the code is derivable fromthe vehicle's location as determined, for example, by the GPS that thisis certainly a preferred method for practicing the teachings disclosedherein.

Note that different people may operate a particular vehicle and when aconnection to the Internet is achieved, the Internet may not know theidentity of the operator or passenger, for the case where the passengerwishes to operate the Internet. One solution is for the operator orpassenger to insert a smart card, plug in their PDA or cell phone orotherwise electronically identify themselves.

Transponders are contemplated by the inventions disclosed hereinincluding SAW, RFID or other technologies that can be embedded withinthe roadway or on objects beside the roadway, in vehicle license plates,for example. An interrogator within the vehicle transmits power to thetransponder and receives a return signal. Alternately, as disclosedabove, the responding device can have its own source of power so thatthe vehicle located interrogator need only receive a signal in responseto an initiated request. The source of power can be a battery,connection to an electric power source such as an AC circuit, solarcollector, or in some cases the energy can be harvested from theenvironment where vibrations, for example, are present. The range of alicense-mounted transponder, for example, can be greatly increased ifsuch a vibration-based energy harvesting system is incorporated.

Some of the systems disclosed herein make use of an energy beam thatinterrogates a reflector or retransmitting device. Such a device can bea sign as well as any pole with a mounted reflector, for example. Insome cases, it will be possible for the infrastructure device to modifyits message so that when interrogated it can provide information inaddition to its location. A speed limit sign, for example, can return avariable code indicating the latest speed limit that then could havebeen set remotely by some responsible authority. Alternately,construction zones frequently will permit one speed when workers areabsent and another when workers are present. The actual permitted speedcan be transmitted to the vehicle when it is interrogated or as thevehicle passes. Thus, a sign or reflector could also be an active signand this sign could be an active matrix organic display and solarcollector that does not need a connection to a power line and yetprovides both a visual message and transmits that message to the vehiclefor in-vehicle signage. Each of these systems has the advantage thatsince minimal power is required to operate the infrastructure-basedsign, it would not require connection to a power line. It would onlytransmit when asked to do so either by a transmission from the vehicleor by sensing that a vehicle is present.

A key marketing point for OnStar® is their one button system. This ideacan be generalized in that a vehicle operator can summon help orotherwise send a desired message to a remoter site by pushing a singlebutton. The message sent can just be a distress message or it canperform a particular function selected by the vehicle depending on theemergency or from a menu selected by the operator. Thus, the OnStar® onebutton concept is retained but the message can be different fordifferent situations.

10. The RtZF™ System

10.1 Technical Issues

From the above discussion, two conclusions should be evident. There aresignificant advantages in accurately knowing where the vehicle, theroadway and other vehicles are and that possession of this informationis the key to reducing fatalities to zero. Second, there are manytechnologies that are already in existence that can provide thisinformation to each vehicle. Once there is a clear, recognized directionthat this is the solution, then many new technologies will emerge. Thereis nothing inherently expensive about these technologies and once theproduct life cycle is underway, the added cost to vehicle purchaserswill be minimal. Roadway infrastructure costs will be minimal and systemmaintenance costs almost non-existent.

Most importantly, the system has the capability of reducing fatalitiesto zero!

The accuracy of DGPS has been demonstrated numerous times in smallcontrolled experiments, most recently by the University of Minnesota andSRI.

The second technical problem is the integrity of the signals beingreceived and the major cause of the lack of integrity is the multi-patheffect. Considerable research has gone into solving the multi-patheffect and Trimble, for example, claims that this problem is no longeran issue.

The third area is availability of GPS and DGPS signals to the vehicle asit is driving down the road. The system is designed to toleratetemporary losses of signal, up to a few minutes. That is the primefunction of the inertial navigation system (INS or IMU). Prolongedabsence of the GPS signal will significantly degrade system performance.There are two primary causes of lack of availability, namely, temporarycauses and permanent causes. Temporary causes result from a car drivingbetween two trucks for an extended period of time, blocking the GPSsignals. The eventual solution to this problem is to change the laws toprevent trucks from traveling on both sides of an automobile. If thisremains a problem, a warning will be provided to the driver that he/sheis losing system integrity and therefore he/she should speed up or slowdown to regain a satellite view. This could also be done automatically.Additionally, the vehicle can obtain its location information throughvehicle-to-vehicle communication plus a ranging system so that if thevehicle learns the exact location of the adjacent vehicle and itsrelative location, then it can determine its absolute location. Ofcourse, if the precise positioning system is able to interrogate theenvironment, then the problem is also solved via the PPS system.

Permanent blockage of the GPS signals, as can come from operating thevehicle in a tunnel or downtown of a large city, can be correctedthrough the use of pseudolites or other guidance systems such as theSnapTrack system or the PPS described here. This is not a seriousproblem since very few cars run off the road in a tunnel or in downtownareas. Eventually, it is expected that the PPS will become ubiquitousthereby rendering GPS as the backup system. Additional methods forlocation determine to aid in reacquiring the satellite lock includevarious methods based on cell phones and other satellite systems such asthe Skybitz system that can locate a device with minimal information.

The final technical impediment is the operation of the diagnostic systemthat verifies that the system is operating properly. This requires anextensive failure mode and effect analysis and the design of adiagnostic system that answers all of the concerns of the FMEA.

10.2 Cost Issues

The primary cost impediment is the cost of the DGPS hardware. A singlebase station and roving receiver that will give an accuracy of 2centimeters (1σ) currently costs about $25,000. This is a temporarysituation brought about by low sales volume. Since there is nothingexotic in the receiving unit, the cost can be expected to follow typicalautomotive electronic life-cycle costs and therefore the projected highvolume production cost of the electronics for the DGPS receivers isbelow $100 per vehicle. In the initial implementation of the system, anOmniSTAR™ DGPS system will be used providing an accuracy of 6 cm. TheU.S. national DGPS system is now coming on line and thus the cost of theDGPS corrections will soon approach zero.

A similar argument can be made for the inertial navigation system.Considerable research and development effort is ongoing to reduce thesize, complexity and cost of these systems. Three technologies are vyingfor this rapidly growing market: laser gyroscopes, fiber-optic lasers,and MEMS systems. The cost of these units today range from a few hundredto ten thousand dollars each, however, once again this is due to thevery small quantity being sold. Substantial improvements are being madein the accuracies of the MEMS systems and it now appears that such asystem will be accurate enough for RtZF™ purposes. The cost of thesesystems in high-volume production is expected to be on the order of tendollars each. This includes at least a yaw rate sensor with threeaccelerometers and probably three angular rate sensors. The accuracy ofthese units is currently approximately 0.003 degrees per second. This isa random error which can be corrected somewhat by the use of multiplevibrating elements. A new laser gyroscope has recently been announced byIntellisense Corporation which should provide a dramatic cost reductionand accuracy improvement.

One of the problems keeping the costs high is the need in the case ofMEMS sensors to go through an extensive calibration process where theeffects of all influences such as temperature, pressure, vibration, andage is determined and a constitute equation is derived for each device.A key factor in the system of the inventions here is that this extensivecalibration process is eliminated and the error corrections for the IMUare determined after it is mounted on the vehicle through the use of aKalman filter, or equivalent, coupled with input from the GPS and DGPSsystem and the precise positioning system. Other available sensors arealso used depending on the system. These include a device for measuringthe downward direction of the earth's magnetic field, a flux gagecompass, a magnetic compass, a gravity sensor, the vehicle speedometerand odometer, the ABS sensors including wheel speed sensors, andwhatever additional appropriate sensors that are available. Over time,the system can learn of the properties of each component that makes upthe IMU and derive the constituent equation for that component which,although it will have little effect on the instantaneous accuracy of thecomponent, it will affect the long term accuracy and speed up thecalculations.

Eventually, when most vehicles on the road have the RtZF™ system,communication between the vehicles can be used to substantially improvethe location accuracy of each vehicle as described above.

The cost of mapping the CONUS is largely an unknown at this time.OmniSTAR® has stated that they will map any area with sufficient detailat a cost of $300 per mile. They have also indicated the cost will dropsubstantially as the number of miles to be mapped increases. Thismapping would be done by helicopter using cameras and their laserranging system. Another method is to outfit a ground vehicle withequipment that will determine the location of the lane and shoulderboundaries of road and other information. Such a system has been usedfor mapping a Swedish highway. One estimate is that the mapping of aroad will be reduced to approximately $50 per mile for major highwaysand rural roads and a somewhat higher number for urban areas. The goalis to map the country to an accuracy of 2 to 10 centimeters (1σ).

Related to the costs of mapping is the cost of converting the raw dataacquired either by helicopter or by ground vehicle into a usable mapdatabase. The cost for manually performing this vectorization processhas been estimated at $100 per mile by OmniSTAR®. This process can besubstantially simplified through the use of raster-to-vector conversionsoftware. Such software is currently being used for converting handdrawings into CAD systems, for example. The Intergraph Corp. provideshardware and software for simplifying this task. It is thereforeexpected that the cost for vectorization of the map data will followproportionately a similar path to the cost of acquiring the data and mayeventually reach $10 to $20 per mile for the rural mapping and $25 to a$50 per mile for urban areas. Considering that there are approximatelyfour million miles of roads in the CONUS, and assuming we can achieve anaverage of $150 for acquiring the data and converting the data to a GISdatabase can be achieved, the total cost for mapping all of the roads inU.S. will amount to $600 million. This cost would obviously be spreadover a number of years and thus the cost per year is manageable andsmall in comparison to the $215 billion lost every year due to death,injury and lost time from traffic congestion.

Another cost factor is the lack of DGPS base stations. The initialanalysis indicated that this would be a serious problem as using thelatest DGPS technology requires a base station every 30 miles. Uponfurther research, however, it has been determined that the OmniSTARcompany has now deployed a nationwide WADGPS system with 6 cm accuracy.The initial goal of the RtZF™ system was to achieve 2 cm accuracy forboth mapping and vehicle location. The 2 cm accuracy can be obtained inthe map database since temporary differential base stations will beinstalled for the mapping purposes. By relaxing the 2 cm requirement to6 cm, the need for base stations every 30 miles disappears and the costof adding a substantial number of base stations is no longer a factor.

The next impediment is the lack of a system for determining when changesare planned for the mapped roads. This will require communication withall highway and road maintenance organizations in the mapped area.

A similar impediment to the widespread implementation of this RtZF™system is the lack of a communication system for supplying map changesto the equipped vehicles.

10.3 Educational Issues

A serious impediment to the implementation of this system that isrelated to the general lack of familiarity with the system, is thebelief that significant fatalities and injuries on U.S. highways are afact of life. This argument is presented in many forms such as “theperfect is the enemy of the good”. This leads to the conclusion that anysystem that portends to reduce injury should be implemented rather thantaking the viewpoint that driving an automobile is a process and as suchit can be designed to achieve perfection. As soon as it is admitted thatperfection cannot be achieved, then any fatality gets immediatelyassociated with this fact. This of course was the prevailing view amongall manufacturing executives until the zero defects paradigm shift tookplace. The goal of the “Zero Fatalities”™ program is not going to beachieved in a short period of time. Nevertheless, to plan anything shortof zero fatalities is to admit defeat and to thereby allow technologiesto enter the market that are inconsistent with a zero fatalities goal.

10.4 Potential Benefits when the System is Deployed.

10.4.1 Assumptions for the Application Benefits Analysis

-   -   The high volume incremental cost of an automobile will be $200.    -   The cost of DGPS correction signals will be a onetime charge of        $50 per vehicle.    -   The benefits to the vehicle owner from up-to-date maps and to        the purveyors of services located on these maps. will cover the        cost of updating the maps as the roads change.    -   The cost of mapping substantially all roads in the CONUS will be        $600 million.    -   The effects of phasing in the system will be ignored.    -   There are 15 million vehicles sold in the U.S. each year.    -   Of the 40,000 plus people killed on the roadways, at least 10%        are due to road departure, yellow line infraction, stop sign        infraction, excessive speed and other causes which will be        eliminated by the Phase Zero deployment.    -   $165 billion are lost each year due to highway accidents.    -   The cost savings due to secondary benefits will be ignored.        10.4.2 Analysis Methods Described.

The analysis method will be quite simple. Assume that 10% of thevehicles on the road will be equipped with RtZF™ systems in the firstyear and that this will increase by 10% each year. Ten percent or 4000lives will be saved and a comparable percentage of injuries. Thus, inthe first year, one percent of $165 billion dollars will be saved or$1.65 billion. In the second year, this saving will be $3.3 billion andthe third year $4.95 billion. The first-year cost of implementation ofthe system will be $600 million for mapping and $3.75 billion forinstallation onto vehicles. The first year cost therefore will be $4.35billion and the cost for the second and continuing years will be $3.75billion. Thus, by the third year, the benefits exceed the costs and bythe 10th year, the benefits will reach $16.5 billion compared with costsof $3.75 billion yielding a benefits-to-cost ratio of more than 4.

Before the fifth year of deployment, it is expected that the other partsof the RtZF™ system will begin to be deployed and that the benefitstherefore are substantially understated. It is also believed that the$250 price for the Phase Zero system on a long-term basis is high and itis expected that the price to drop substantially. No attempt has beenmade to estimate the value of the time saved in congestion or efficientoperation of the highway system. Estimates that have been presented byothers indicate that as much as a two to three times improvement intraffic through flow is possible. Thus, a substantial portion of the $50billion per year lost in congestion delays will also be saved when thefull RtZF™ system is implemented.

It is also believed that the percentage reduction of fatalities andinjuries has been substantially understated. For the first time, therewill be some control over the drunk or otherwise incapacitated driver.If the excessive speed feature is implemented, then gradually the costof enforcing the nation's speed limits will begin to be substantiallyreduced. Since it is expected that large trucks will be among firstvehicles to be totally covered with the system, perhaps on a retrofitbasis, it is expected that the benefits to commercial vehicle owners andoperators will be substantial. The retrofit market may rapidly developand the assumptions of vehicles with deployed systems may be low. Noneof these effects have been taken into account in the above analysis.

The automated highway systems resulting from RtZF™ implementation isexpected to double or even triple in effective capacity by increasingspeeds and shortening distances between vehicles. Thus, the effect onhighway construction cost could be significant.

10.5 Initial System Deployment

The initial implementation of the RtZF™ system would include thefollowing services:

1. A warning is issued to the driver when the driver is about to departfrom the road.

2. A warning is issued to the driver when the driver is about to cross ayellow line or other lane boundary.

3. A warning is provided to the driver when the driver is exceeding asafe speed limit for the road geometry.

4. A warning is provided to the driver when the driver is about to gothrough a stop sign without stopping.

5. A warning is provided to the driver when the driver is about to runthe risk of a rollover.

6. A warning will be issued prior to a rear end impact by the equippedvehicle.

7. In-vehicle signage will be provided for highway signs (perhaps with amultiple language option).

8. A recording will be logged whenever a warning is issued.

10.6 Other Uses

The RtZF™ system can replace vehicle crash and rollover sensors forairbag deployment and other sensors now on or being considered forautomobile vehicles including pitch, roll and yaw sensors. Thisinformation is available from the IMU and is far more accurate thanthese other sensors. It can also be found by using carrier phase GPS byadding more antennas to the vehicle. Additionally, once the system is inplace for land vehicles, there will be many other applications such assurveying, vehicle tracking and aircraft landing which will benefit fromthe technology and infrastructure improvements. The automobile safetyissue and ITS will result in the implementation of a national systemwhich provides any user with low cost equipment the ability to knowprecisely where he is within centimeters on the face of the earth. Manyother applications will undoubtedly follow.

10.7 Road Departure

FIG. 4 is a logic diagram of the system 50 in accordance with theinvention showing the combination 40 of the GPS and DGPS processingsystems 42 and an inertial reference unit (IRU) or inertial navigationsystem (INS) or Inertial Measurement Unit (IMU) 44. The GPS systemincludes a unit for processing the received information from thesatellites 2 of the GPS satellite system, the information from thesatellites 30 of the DGPS system and data from the inertial referenceunit 44. The inertial reference unit 44 contains accelerometers andlaser or MEMS gyroscopes.

The system shown in FIG. 4 is a minimal RtZF™ system that can be used toprevent road departure, lane crossing and intersection accidents, whichtogether account for more than about 50% of the fatal accidents in theU.S.

Map database 48 works in conjunction with a navigation system 46 toprovide a warning to the driver when he or she is about to run off theroad, cross a center (yellow) line, run a stop sign, or run a redstoplight. The map database 48 contains a map of the roadway to anaccuracy of 2 cm (1σ), i.e., data on the edges of the lanes of theroadway and the edges of the roadway, and the location of all stop signsand stoplights and other traffic control devices such as other types ofroad signs. Another sensor, not shown, provides input to the vehicleindicating that an approaching stoplight is red, yellow or green.Navigation system 46 is coupled to the GPS and DGPS processing system42. For this simple system, the driver is warned if any of the aboveevents is detected by a driver warning system 45 coupled to thenavigation system 46. The driver warning system 45 can be an alarm,light, buzzer or other audible noise, or, preferably, a simulated rumblestrip for yellow line and “running off of road” situations and acombined light and alarm for the stop sign and stoplight infractions.

10.8 Accident Avoidance

FIG. 5 is a block diagram of the more advanced accident avoidance systemof this invention and method of the present invention illustratingsystem sensors, transceivers, computers, displays, input and outputdevices and other key elements.

As illustrated in FIG. 5, the vehicle accident avoidance system isimplemented using a variety of microprocessors and electronic circuits100 to interconnect and route various signals between and among theillustrated subsystems. GPS receiver 52 is used to receive GPS radiosignals as illustrated in FIG. 1. DGPS receiver 54 receives thedifferential correction signals from one or more base stations eitherdirectly or via a geocentric stationary or LEO satellite, an earth-basedstation or other means. Inter-vehicle communication subsystem 56 is usedto transmit and receive information between various nearby vehicles.This communication will in general take place via broad band orultra-broad band communication techniques, or on dedicated frequencyradio channels, or in the preferred mode, noise communication system asdescribed above. This communication may be implemented using multipleaccess communication methods including FDMA, TDMA, or CDMA, or noisecommunication system, in a manner to permit simultaneous communicationwith and between a plurality of vehicles. Other forms of communicationbetween vehicles are possible such as through the Internet. Thiscommunication may include such information as the precise location of avehicle, the latest received signals from the GPS satellites in view,other road condition information, emergency signals, hazard warnings,vehicle velocity and intended path, and any other information which isuseful to improve the safety of the vehicle road system.

Infrastructure communication system 58 permits bidirectionalcommunication between the host vehicle and the infrastructure andincludes such information transfer as updates to the digital maps,weather information, road condition information, hazard information,congestion information, temporary signs and warnings, and any otherinformation which can improve the safety of the vehicle highway system.

Cameras 60 are used generally for interrogating environment nearby thehost vehicle for such functions as blind spot monitoring, backupwarnings, anticipatory crash sensing, visibility determination, lanefollowing, and any other visual information which is desirable forimproving the safety of the vehicle highway system. Generally, thecameras will be sensitive to infrared and/or visible light, however, insome cases a passive infrared camera will the used to detect thepresence of animate bodies such as deer or people on the roadway infront of the vehicle. Frequently, infrared or visible illumination willbe provided by the host vehicle.

Radar 62 is primarily used to scan an environment close to and furtherfrom the vehicle than the range of the cameras and to provide an initialwarning of potential obstacles in the path of the vehicle. The radar 62can also be used when conditions of a reduced visibility are present toprovide advance warning to the vehicle of obstacles hidden by rain, fog,snow etc. Pulsed, continuous wave, noise or micropower impulse radarsystems can be used as appropriate. Also, Doppler radar principles canbe used to determine the object to host vehicle relative velocity.

Laser or terahertz radar 64 is primarily used to illuminate potentialhazardous objects in the path of the vehicle. Since the vehicle will beoperating on accurate mapped roads, the precise location of objectsdiscovered by the radar or camera systems can be determined using rangegating and scanning laser radar as described above or by phasetechniques.

The driver warning system 66 provides visual and/or audible warningmessages to the driver or others that a hazard exists. In addition toactivating a warning system within the vehicle, this system can activatesound and/or light systems to warn other people, animals, or vehicles ofa pending hazardous condition. In such cases, the warning system couldactivate the vehicle headlights, tail lights, horn and/or thevehicle-to-vehicle, Internet or infrastructure communication system toinform other vehicles, a traffic control station or other base station.This system will be important during the early stages of implementationof RtZF™, however as more and more vehicles are equipped with thesystem, there will be less need to warn the driver or others ofpotential problems.

Map database subsystem 68, which could reside on an external memorymodule, will contain all of the map information such as road edges up to2 cm accuracy, the locations of stop signs, stoplights, lane markersetc. as described in detail above. The fundamental map data can beorganized on read-only magnetic or optical memory with a read/writeassociated memory for storing map update information. Alternatively, themap information can be stored on rewritable media that can be updatedwith information from the infrastructure communication subsystem 58.This updating can take place while the vehicle is being operated or,alternatively, while the vehicle is parked in a garage or on the street.

Three servos are provided for controlling the vehicle during the laterstages of implementation of the RtZF™ product and include a brake servo70, a steering servo 72, and a throttle servo 74. The vehicle can becontrolled using deterministic, fuzzy logic, neural network or,preferably, neural-fuzzy algorithms.

As a check on the inertial system, a velocity sensor 76 based on a wheelspeed sensor, or ground speed monitoring system using lasers, radar orultrasonics, for example, can be provided for the system. A radarvelocity meter is a device which transmits a noise modulated radar pulsetoward the ground at an angle to the vertical and measures the Dopplervelocity of the returned signal to provide an accurate measure of thevehicle velocity relative to the ground. Another radar device can bedesigned which measures the displacement of the vehicle. Othermodulation techniques and other radar systems can be used to achievesimilar results. Other systems are preferably used for this purpose suchas the GPS/DGPS or precise position systems.

The inertial navigation system (INS), sometimes called the inertialreference unit or IRU, comprises one or more accelerometers 78 and oneor more gyroscopes 80. Usually, three accelerometers would be requiredto provide the vehicle acceleration in the latitude, longitude andvertical directions and three gyroscopes would be required to providethe angular rate about the pitch, yaw and roll axes. In general, agyroscope would measure the angular rate or angular velocity. Angularacceleration may be obtained by differentiating the angular rate.

A gyroscope 80, as used herein in the IRU, includes all kinds ofgyroscopes such as MEMS-based gyroscopes, fiber optic gyroscopes (FOG)and accelerometer based gyroscopes.

Accelerometer-based gyroscopes encompass a situation where twoaccelerometers are placed apart and the difference in the accelerationis used to determine angular acceleration and a situation where anaccelerometer is placed on a vibrating structure and the Coriolis effectis used to obtain the angular velocity.

The possibility of an accelerometer-based gyroscope 80 in the IRU ismade possible by construction of a suitable gyroscope by InterstateElectronics Corporation (IEC). IEC manufactures IMUs in volume based onμSCIRAS (micro-machined Silicon Coriolis Inertial Rate and AccelerationSensor) accelerometers. Detailed information about this device can befound at the IEC website at iechome.com.

There are two ways to measure angular velocity (acceleration) usingaccelerometers. The first way involves installing the accelerometers ata distance from one another and calculating the angular velocity by thedifference of readings of the accelerometers using dependencies betweenthe centrifugal and tangential accelerations and the angularvelocity/acceleration. This way requires significant accuracy of theaccelerometers.

The second way is based on the measurement of the Coriolis accelerationthat arises when the mass of the sensing element moves at a relativelinear speed and the whole device performs a transportation rotationabout the perpendicular axis. This principle is a basis of allmechanical gyroscopes, including micromachined ones. The difference ofthis device is that the micromachined devices aggregate the linearoscillation excitation system and the Coriolis acceleration measurementsystem, while two separate devices are used in the proposed secondmethod. The source of linear oscillations is the mechanical vibrationsuspension, and the Coriolis acceleration sensors are the micromachinedaccelerometers. On one hand, the presence of two separate devices makesthe instrument bigger, but on the other hand, it enables the use of moreaccurate sensors to measure the Coriolis acceleration. In particular,compensating accelerometer systems could be used which are more accurateby an order of magnitude than open structures commonly used inmicromachined gyroscopes.

Significant issues involved in the construction of anaccelerometer-based gyroscope are providing a high sensitivity of thedevice, a system for measuring the suspension vibration, separating thesignals of angular speed and linear acceleration; filtering noise in theoutput signals of the device at the suspension frequency, providing acorrelation between errors in the channels of angular speed and linearacceleration, considering the effect of nonlinearity of theaccelerometers and the suspension on the error of the output signals.

A typical MEMS-based gyroscope uses a quartz tuning fork. The vibrationof the tuning fork, along with applied angular rotation (yaw rate of thecar), creates Coriolis acceleration on the tuning fork. An accelerometeror strain gage attached to the tuning fork measures the minute Coriolisforce. Signal output is proportional to the size of the tuning fork. Togenerate enough output signal, the tuning fork must vibrate forcefully.Often, this can be accomplished with a high Q structure. Manufacturersoften place the tuning fork in a vacuum to minimize mechanical dampingby air around the tuning fork. High Q structures can be fairly fragile.

The gyroscope often experiences shock and vibration because it must berigidly connected to the car to accurately measure yaw rate. Thismechanical noise can introduce signals to the Coriolis pick-offaccelerometer that is several orders of magnitude higher than thetuning-fork-generated Coriolis signal. Separating the signal from thenoise is not easy. Often, the shock or vibration saturates the circuitryand makes the gyroscope output unreliable for a short time.

Conventional MEMS-based gyroscopes are usually bulky (100 cm³ or more isnot uncommon). This is partly the result of the addition of mechanicalantivibration mounts, which are incorporated to minimize sensitivity toexternal vibration.

New MEMS-based gyroscopes avoid these shortcomings, though. For example,Analog Devices' iMEMS gyro is expected to be 7 by 7 by 3 mm (0.15 cm³).Rather than quartz, it uses a resonating polysilicon beam structure,which creates the velocity element that produces the Coriolis force whenangular rate is presented to it. At the outer edges of the polysiliconbeam, orthogonal to the resonating motion, a capacitive accelerometermeasures the Coriolis force. The gyroscope has two sets of beams inantiphase that are placed next to each other, and their outputs are readdifferentially, attenuating external vibration sensitivity.

An accelerometer 78, as used herein in the IRU, includes conventionalpiezoelectric-based accelerometers, MEMS-based accelerometers (such asmade by Analog Devices) and the type as described in US06182509 entitled“Accelerometer without proof mass”.

Display subsystem 82 includes an appropriate display driver and either aheads-up or other display system for providing system information to thevehicle operator. The information can be in the form of non-criticalinformation such as the location of the vehicle on a map, as selected bythe vehicle operator and/or it can include warning or other emergencymessages provided by the vehicle subsystems or from communication withother vehicles or the infrastructure. An emergency message that the roadhas been washed out ahead, for example, would be an example of such amessage.

Generally, the display will make use of icons when the position of thehost vehicle relative to obstacles or other vehicles is displayed.Occasionally, as the image can be displayed especially when the objectcannot be identified.

A general memory unit 84 which can comprise read-only memory or randomaccess memory or any combination thereof, is shown. This memory module,which can be either located at one place or distributed throughout thesystem, supplies the information storage capability for the system.

For advanced RtZF™ systems containing the precise positioningcapability, subsystem 86 provides the capability of sending andreceiving information to infrastructure-based precise positioning tagsor devices which may be based on noise or micropower impulse radartechnology, radar reflector or RFIR technology or equivalent. Onceagain, the PPS system can also be based on a signature analysis usingthe adaptive associative memory technology or equivalent.

In some locations where weather conditions can deteriorate and degraderoad surface conditions, various infrastructure-based sensors can beplaced either in or adjacent to the road surface. Subsystem 88 isdesigned to interrogate and obtained information from such road-basedsystems. An example of such a system would be an RFID tag containing atemperature sensor. This device may be battery-powered or, preferably,would receive its power from the vehicle-mounted interrogator, or otherhost vehicle-mounted source, as the vehicle passes nearby the device. Inthis manner, the vehicle can obtain the temperature of the road surfaceand receive advanced warning when the temperature is approachingconditions which could cause icing of the roadway, for example. An RFIDbased on a surface acoustic wave (SAW) device is one preferred exampleof such a sensor, see U.S. Pat. No. 6,662,642. An infrared sensor on thevehicle can also be used to determine the road temperature and theexistence of ice or snow.

In order to completely eliminate automobile accidents, a diagnosticsystem is required on the vehicle that will provide advanced warning ofany potential vehicle component failures. Such a system is described inU.S. Pat. No. 5,809,437 (Breed).

For some implementations of the RtZF™ system, stoplights will be fittedwith transmitters which will broadcast a signal when the light is red.Such a system could make use of the vehicle noise communication systemas described above. This signal can be then received by a vehicle thatis approaching the stoplight provided that vehicle has the proper sensoras shown as 92. Alternatively, a camera can be aimed in the direction ofstoplights and, since the existence of the stoplight will be known bythe system, as it will have been recorded on the map, the vehicle willknow when to look for a stoplight and determine the color of the light.

An alternative idea is for the vehicle to broadcast a signal to thestoplight if, via a camera or other means, it determines that the lightis red. If there are no vehicles coming from the other direction, thelight can change permitting the vehicle to proceed without stopping.Similarly, if the stoplight has a camera, it can look in all directionsand control the light color depending on the number of vehiclesapproaching from each direction. A system of phasing vehicles can alsobe devised whereby the speed of approaching vehicles is controlled sothat they interleave through the intersection and the stoplight may notbe necessary.

Although atomic clocks are probably too expensive to the deployed onautomobiles, nevertheless there has been significant advances recentlyin the accuracy of clocks to the extent that it is now feasible to placea reasonably accurate clock as a subsystem 94 to this system. Since theclock can be recalibrated from each DGPS transmission, the clock driftcan be accurately measured and used to predict the precise time eventhough the clock by itself may be incapable of doing so. To the extentthat the vehicle contains an accurate time source, the satellites inview requirement can temporarily drop from 4 to 3. An accurate clockalso facilitates the carrier phase DGPS implementations of the system asdiscussed above. Additionally, as long as a vehicle knows approximatelywhere it is on the roadway, it will know its altitude from the map andthus one less satellite is necessary.

Power must be supplied to the system as shown by power subsystem 96.Certain operator controls are also permitted as illustrated in subsystem98.

The control processor or central processor and circuit board subsystem100 to which all of the above components 52–98 are coupled, performssuch functions as GPS ranging, DGPS corrections, image analysis, radaranalysis, laser radar scanning control and analysis of receivedinformation, warning message generation, map communication, vehiclecontrol, inertial navigation system calibrations and control, displaycontrol, precise positioning calculations, road condition predictions,and all other functions needed for the system to operate according todesign.

A display could be provided for generating and displaying warningmessages which is visible to the driver and/or passengers of thevehicle. The warning could also be in the form of an audible tone, asimulated rumble strip and light and other similar ways to attract theattention of the driver and/or passengers.

Vehicle control also encompasses control over the vehicle to preventaccidents. By considering information from the map database 48 of thenavigation system 46, and the position of the vehicle obtained via GPSsystems, a determination can be made whether the vehicle is about to runoff the road, cross a yellow line and run a stop sign, as well as theexistence or foreseen occurrence of other potential crash situations.The color of an approaching stoplight can also be factored in thevehicle control.

FIG. 5A shows a selected reduced embodiment of the accident avoidancesystem shown in FIG. 5. The system includes an inertial reference unitincluding a plurality of accelerometers and gyroscopes, namelyaccelerometers 78A, preferably three of any type disclosed above, andgyroscopes 80A, preferably three of any type disclosed above. A clock94A is provided to obtain a time base or time reference. This systemwill accurately determine the motion (displacement, acceleration and/orvelocity) of the vehicle in 6 degrees of freedom (3 displacements(longitudinal, lateral and vertical)) via the accelerometers 78A andthree rotations (pitch, yaw and roll) via the gyroscopes 80A. As such,along with a time base from clock 94A, the processor 100A can determinethat there was an accident and precisely what type of accident it was interms of the motion of the vehicle (frontal, side, rear and rollover).This system is different from a crash sensor in that this system canreside in the passenger compartment of the vehicle where it is protectedfrom actually being in the accident crush and/or crash zones and thus itdoes not have to forecast the accident severity. It knows the resultingvehicle motion and therefore exactly what the accident was and what theinjury potential is. A typical crash sensor can get destroyed or atleast rotated during the crash and thus will not determine the realseverity of the accident.

Processor 100A is coupled to the inertial reference unit and also iscapable of performing the functions of vehicle control, such as viacontrol of the brake system 70A, steering system 72A and velocity sensor74A, crash sensing, rollover sensing, cassis control sensing, navigationfunctions and accident prevention as discussed herein.

Preferably, a Kalman filter is used to optimize the data from theinertial reference unit as well as other input sources of data, signalsor information. Also, a neural network, fuzzy logic or neural-fuzzysystem could be used to reduce the data obtained from the varioussensors to a manageable and optimal set. The actual manner in which aKalman filter can be constructed and used in the invention would be leftto one skilled in the art. Note that in the system of the inventionsdisclosed herein, the extensive calibration process carried on by othersuppliers of inertial sensors is not required since the systemperiodically corrects the errors in the sensors and revises thecalibration equation. This in some cases can reduce the manufacturingcost on the IMU by a factor of ten.

Further, the information from the accelerometers 78A and gyroscopes 80Ain conjunction with the time base or reference is transmittable via thecommunication system 56A,58A to other vehicles, possibly for the purposeof enabling other vehicles to avoid accidents with the host vehicle,and/or to infrastructure.

One particularly useful function would be for the processor to send datafrom, or data derived from, the accelerometers and gyroscopes relatingto a crash, i.e., indicative of the severity of the accident with thepotential for injury to occupants, to a monitoring location for thedispatch of emergency response personnel, i.e., an EMS facility or firestation. Other telematics functions could also be provided.

10.9 Exterior Surveillance System

FIG. 6 is a block diagram of the host vehicle exterior surveillancesystem. Cameras 60 are primarily intended for observing the immediateenvironment of the vehicle. They are used for recognizing objects thatcould be most threatening to the vehicle, i.e., closest to the vehicle.These objects include vehicles or other objects that are in the vehicleblind spot, objects or vehicles that are about to impact the hostvehicle from any direction, and objects either in front of or behind thehost vehicle which the host vehicle is about to impact. These functionsare normally called blind spot monitoring and collision anticipatorysensors.

As discussed above, the cameras 60 can use naturally occurring visibleor infrared radiation, or other parts of the electromagnetic spectrumincluding terahertz and x-rays, or they may be supplemented with sourcesof visible or infrared illumination from the host vehicle. Note thatthere generally is little naturally occurring terahertz radiation otherthan the amount that occurs in black body radiation from all sources.The cameras 60 used are preferably high dynamic range cameras that havea dynamic range exceeding 60 db and preferably exceeding 100 db. Suchcommercially available cameras include those manufactured by thePhotobit Corporation in California and the IMS Chips Company inStuttgart Germany. Alternately, various other means exist for increasingthe effective dynamic range through shutter control or illuminationcontrol using a Kerr or Pockel cell, modulated illumination, externalpixel integration etc.

These cameras are based on CMOS technology and can have the importantproperty that pixels are independently addressable. Thus, the controlprocessor may decide which pixels are to be read at a particular time.This permits the system to concentrate on certain objects of interestand thereby make more effective use of the available bandwidth.

Video processor printed circuit boards or feature extractor 61 can belocated adjacent and coupled to the cameras 60 so as to reduce theinformation transferred to the control processor. The video processorfeature extractor 61 can also perform the function of feature extractionso that all values of all pixels do not need to be sent to the neuralnetwork for identification processing. The feature extraction includessuch tasks as determining the edges of objects in the scene and, inparticular, comparing and subtracting one scene from another toeliminate unimportant background images and to concentrate on thoseobjects which had been illuminated with infrared or terahertz radiation,for example, from the host vehicle. By these and other techniques, theamount of information to be transferred to the neural network issubstantially reduced.

The neural network 63 receives the feature data extracted from thecamera images by the video processor feature extractor 61 and uses thisdata to determine the identification of the object in the image. Theneural network 63 has been previously trained on a library of imagesthat can involve as many as one million such images. Fortunately, theimages seen from one vehicle are substantially the same as those seenfrom another vehicle and thus the neural network 63 in general does notneed to be trained for each type of host vehicle.

As the number of image types increases, modular or combination neuralnetworks can be used to simplify the system.

Although the neural network 63 has in particular been described, otherpattern recognition techniques are also applicable. One such techniqueuses the Fourier transform of the image and utilizes either opticalcorrelation techniques or a neural network trained on the Fouriertransforms of the images rather than on the image itself. In one case,the optical correlation is accomplished purely optically wherein theFourier transform of the image is accomplished using diffractiontechniques and projected onto a display, such as a garnet crystaldisplay, while a library of the object Fourier transforms is alsodisplayed on the display. By comparing the total light passing throughthe display, an optical correlation can be obtained very rapidly.Although such a technique has been applied to scene scanning by militaryhelicopters, it has previously not been used in automotive applications.

The laser radar system 64 is typically used in conjunction with ascanner 65. The scanner 65 typically includes two oscillating mirrors,or a MEMS mirror capable of oscillating in two dimensions, which causethe laser light to scan the two-dimensional angular field. Alternately,the scanner can be a solid-state device utilizing a crystal having ahigh index of refraction which is driven by an ultrasonic vibrator asdiscussed above or rotating mirrors. The ultrasonic vibrator establisheselastic waves in the crystal which diffracts and changes the directionof the laser light.

The laser beam can be frequency, amplitude, time, code or noisemodulated so that the distance to the object reflecting the light can bedetermined. The laser light strikes an object and is reflected backwhere it is guided onto a pin diode, or other high speed photo detector.Since the direction of laser light is known, the angular location of thereflected object is also known and since the laser light is modulatedthe distance to the reflected point can be determined. By varyingmodulation frequency of the laser light, or through noise or codemodulation, the distance can be very precisely measured.

Alternatively, the time-of-flight of a short burst of laser light can bemeasured providing a direct reading of the distance to the object thatreflected the light. By either technique, a three-dimensional map can bemade of the surface of the reflecting object. Objects within a certainrange of the host vehicle can be easily separated out using the rangeinformation. This can be done electronically using a technique calledrange gating, or it can be accomplished mathematically based on therange data. By this technique, an image of an object can be easilyseparated from other objects based on distance from the host vehicle.

Since the vehicle knows its position accurately and in particular itknows the lane on which it is driving, a determination can be made ofthe location of any reflective object and in particular whether or notthe reflective object is on the same lane as the host vehicle. This factcan be determined since the host vehicle has a map and the reflectiveobject can be virtually placed on that map to determine its location onthe roadway, for example.

The laser radar system will generally operate in the near infrared partof the electromagnetic spectrum. The laser beam will be of relativelyhigh intensity compared to the surrounding radiation and thus even inconditions of fog, snow, and heavy rain, the penetration of the laserbeam and its reflection will permit somewhat greater distanceobservations than the human driver can perceive. Under the RtZF™ plan,it is recommended that the speed of the host vehicle be limited suchthat vehicle can come to a complete stop in one half or less of thevisibility distance. This will permit the laser radar system to observeand identify threatening objects that are beyond the visibilitydistance, apply the brakes to the vehicle if necessary causing thevehicle to stop prior to an impact, providing an added degree of safetyto the host vehicle.

Radar system 62 is mainly provided to supplement laser radar system. Itis particularly useful for low visibility situations where thepenetration of the laser radar system is limited. The radar system,which is most probably a noise or pseudonoise modulated continuous waveradar, can also be used to provide a crude map of objects surroundingthe vehicle. The most common use for automotive radar systems is foradaptive cruise control systems where the radar monitors the distanceand, in some cases, the velocity of the vehicle immediately in front ofthe host vehicle. The radar system 62 is controlled by the controlprocessor 100.

The display system 82 was discussed previously and can be either a headsup or other appropriate display.

The control processor 100 can be attached to a vehicle special orgeneral purpose bus 110 for transferring other information to and fromthe control processor to other vehicle subsystems.

In interrogating other vehicles on the roadway, a positiveidentification of the vehicle and thus its expected properties such asits size and mass can sometimes be accomplished by laser vibrometry. Bythis method, a reflected electromagnetic wave can be modulated based onthe vibration that the vehicle is undergoing. Since this vibration iscaused at least partially by the engine, and each class of engine has adifferent vibration signature, this information can be used to identifythe engine type and thus the vehicle. This technique is similar to oneused to identify enemy military vehicles by the U.S. military. It isalso used to identify ships at sea using hydrophones. In the presentcase, a laser beam is directed at the vehicle of interest and thereturned reflected beam is analyzed such as with a Fourier transform todetermine the frequency makeup of the beam. This can then be related toa vehicle to identify its type either through the use of a look-up tableor neural network or other appropriate method. This information can thenbe used as information in connection with an anticipatory sensor as itwould permit a more accurate estimation of the mass of a potentiallyimpacting vehicle.

Once the vehicle knows where it is located, this information can bedisplayed on a heads-up display and if an occupant sensor has determinedthe location of the eyes of the driver, the road edges, for example, andother pertinent information from the map database can be displayedexactly where they would be seen by the driver. For the case of drivingin dense fog or on a snow covered road, the driver will be able to seethe road edges perhaps exactly or even better than the real view, insome cases. Additionally, other information gleaned by the exteriormonitoring system can show the operator the presence of other vehiclesand whether they represent a threat to the host vehicle (see for example“Seeing the road ahead”, GPS World Nov. 1, 2003, which describes asystem incorporating many of the current assignee's invention ideasdescribed herein).

10.10 Corridors

FIG. 7 shows the implementation of the invention in which a vehicle 18is traveling on a roadway in a defined corridor in the direction X. Eachcorridor is defined by lines 14. If the vehicle is traveling in onecorridor and strays in the direction Y so that it moves along the line22, e.g., the driver is falling asleep, the system on board the vehiclein accordance with the invention will activate a warning. Morespecifically, the system continually detects the position of thevehicle, such as by means of the GPS, DGPS and/or PPS, and has thelocations of the lines 14 defining the corridor recorded in its mapdatabase. Upon an intersection of the position of the vehicle and one ofthe lines 14 as determined by a processor, the system may be designed tosound an alarm to alert the driver to the deviation or possibly evencorrect the steering of the vehicle to return the vehicle to within thecorridor defined by lines 14.

FIG. 8 shows the implementation of the invention in which a pair ofvehicles 18, 26 are traveling on a roadway each in a defined corridordefined by lines 14 and each equipped with a system in accordance withthe invention. The system in each vehicle 18, 26 will receive datainforming it of the position of the other vehicle and prevent accidentsfrom occurring, e.g., if vehicle 18 moves in the direction of arrow 20.This can be accomplished via direct wireless broadband communication orany of the other communication methods described above, or throughanother path such as via the Internet or through a base station, whereineach vehicle transmits its best estimate of its absolute location on theearth along with an estimate of the accuracy of this location. If onevehicle has recently passed a precise positioning station, for example,then it will know its position very accurately to within a fewcentimeters. Each vehicle can also send the latest satellite messagesthat it received, permitting each vehicle to precisely determine itsrelative location to the other since the errors in the signals will bethe same for both vehicles. To the extent that both vehicles are neareach other, even the carrier phase ambiguity can be determined and eachvehicle will know its position relative to the other to within betterthan a few centimeters. As more and more vehicles become part of thecommunity and communicate their information to each other, each vehiclecan even more accurately determine its absolute position and especiallyif one vehicle knows its position very accurately, if it recently passeda PPS for example, then all vehicles will know their position withapproximately the same accuracy and that accuracy will be able to bemaintained for as long as a vehicle keeps its lock on the satellites inview. If that lock is lost temporarily, the INS system will fill in thegaps and, depending on the accuracy of that system, the approximate 2centimeter accuracy can be maintained even if the satellite lock is lostfor up to approximately five minutes.

A five minute loss of satellite lock is unlikely except in tunnels or inlocations where buildings or geological features interfere with thesignals. In the building case, the problem can be eliminated through theplacement of PPS stations, or through environmental signature analysis,and the same would be true for the geological obstruction case except inremote areas where ultra precise positioning accuracy is probably notrequired. In the case of tunnels, for example, the cost of adding PPSstations is insignificant compared with the cost of building andmaintaining the tunnel.

10.11 Vehicle Control

FIG. 12 a is a flow chart of the method in accordance with theinvention. The absolute position of the vehicle is determined at 130,e.g., using a GPS, DGPS PPS system, and compared to the edges of theroadway at 134, which is obtained from a memory unit 132. Based on thecomparison at 134, it is determined whether the absolute position of thevehicle is approaching close to or intersects an edge of the roadway at136. If not, then the position of the vehicle is again obtained, e.g.,at a set time interval thereafter, and the process continues. If yes, analarm and/or warning system will be activated or the system will takecontrol of the vehicle (at 140) to guide it to a shoulder of the roadwayor other safe location.

FIG. 12 b is another flow chart of the method in accordance with theinvention similar to FIG. 12 a. Again the absolute position of thevehicle is determined at 130, e.g., using a GPS, DGPS PPS system, andcompared to the location of a roadway yellow line at 142 (or possiblyanother line which indicates an edge of a lane of a roadway), which isobtained from a memory unit 132. Based on the comparison at 144, it isdetermined whether the absolute position of the vehicle is approachingclose to or intersects the yellow line 144. If not, then the position ofthe vehicle is again obtained, e.g., at a set time interval thereafter,and the process continues. If yes, an alarm will sound and/or the systemwill take control of the vehicle (at 146) to control the steering orguide it to a shoulder of the roadway or other safe location.

FIG. 12 c is another flow chart of the method in accordance with theinvention similar to FIG. 12 a. Again the absolute position of thevehicle is determined at 130, e.g., using a GPS, DGPS PPS system, andcompared to the location of a roadway stoplight at 150, which isobtained from a memory unit 132. Based on the comparison at 150, it isdetermined whether the absolute position of the vehicle is approachingclose to a stoplight. If not, then the position of the vehicle is againobtained, e.g., at a set interval thereafter, and the process continues.If yes, a sensor determines whether the stoplight is red (e.g., acamera) and if so, an alarm will sound and/or the system will takecontrol of the vehicle (at 154) to control the brakes or guide it to ashoulder of the roadway or other safe location. A similar flow chart canbe now drawn by those skilled in the art for other conditions such asstop signs, vehicle speed control, collision avoidance etc.

10.12 Intersection Collision Avoidance

FIG. 13 illustrates an intersection of a major road 170 with a lesserroad 172. The road 170 has the right of way and stop signs 174 have beenplaced to control the traffic on the lesser road 172. Vehicles 18 and 26are proceeding on road 172 and vehicle 25 is proceeding on road 170. Avery common accident is caused when vehicle 18 ignores the stop sign 174and proceeds into the intersection where it is struck on the side byvehicle 25 or strikes vehicle 25 on the side.

Using the teachings of this invention, vehicle 18 will know of theexistence of the stop sign and if the operator attempts to proceedwithout stopping, the system will sound a warning and if that warning isnot heeded, the system will automatically bring the vehicle 18 to a stoppreventing it from intruding into the intersection.

Another common accident is where vehicle 18 does in fact stop but thenproceeds forward without noticing vehicle 25 thereby causing anaccident. Since in the fully deployed RtZF™ system, vehicle 18 will knowthrough the vehicle-to-vehicle communication the existence and locationof vehicle 25 and can calculate its velocity, the system can once againtake control of vehicle 18 if a warning is not heeded and preventvehicle 18 from proceeding into the intersection and thereby prevent theaccident.

In the event that the vehicle 25 is not equipped with the RtZF™ system,vehicle 18 will still sense the presence of vehicle 25 through the laserradar, radar and camera systems. Once again, when the position andvelocity of vehicle 25 is sensed, appropriate action can be taken by thesystem in vehicle 18 to eliminate the accident.

In another scenario where vehicle 18 properly stops at the stop sign,but vehicle 26 proceeds without observing the presence of the stoppedvehicle 18, the laser radar, radar and camera systems will all operateto warn the driver of vehicle 26 and if that warning is not heeded, thesystem in vehicle 26 will automatically stop the vehicle 26 prior to itsimpacting vehicle 18. Thus, in the scenarios described above the “Roadto Zero Fatalities”™ system and method of this invention will preventcommon intersection accidents from occurring.

FIG. 14 is a view of an intersection where traffic is controlled bystoplights 180. If the vehicle 18 does not respond in time to a redstoplight, the system as described above will issue a warning and if notheeded, the system will take control of the vehicle 18 to prevent itfrom entering the intersection and colliding vehicle 25. In this case,the stoplight 180 will emit a signal indicating its color, such as byway of the communication system, and/or vehicle 18 will have a cameramounted such that it can observe the color of the stoplight. There areof course other information transfer methods such as through theInternet. In this case, buildings 182 obstruct the view from vehicle 18to vehicle 25 thus an accident can still be prevented even when theoperators are not able to visually see the threatening vehicle. If bothvehicles have the RtZF™ system, they will be communicating and theirpresence and relative positions will be known to both vehicles.

FIG. 15 illustrates the case where vehicle 18 is about to execute aleft-hand turn into the path of vehicle 25. This accident will beprevented if both cars have the RtZF™ system since the locations andvelocities of both vehicles 18, 25 will be known to each other. Ifvehicle 25 is not equipped and vehicle 18 is, then the camera, radar,and laser radar subsystems will operate to prevent vehicle 18 fromturning into the path of vehicle 25. Once again, common intersectionaccidents are prevented by this invention.

The systems described above can be augmented by infrastructure-basedsensing and warning systems. Camera, laser or terahertz radar or radarsubsystems such as placed on the vehicle can also be placed atintersections to warn the oncoming traffic if a collision is likely tooccur. Additionally, simple sensors that sense the signals emitted byoncoming vehicles, including radar, thermal radiation, etc., can be usedto operate warning systems that notify oncoming traffic of potentiallydangerous situations. Thus, many of the teachings of this invention canbe applied to infrastructure-based installations in addition to thevehicle-resident systems.

10.13 Privacy

People do not necessarily want the government to know where they aregoing and therefore will not want information to be transmitted that canidentify the vehicle. The importance of this issue may be overestimated.Most people will not object to this minor infraction if they can get totheir destination more efficiently and safely.

On the other hand, it has been estimated that there are 100,000 vehicleson the road, many of them stolen, where the operators do not want thevehicle to be identified. If an identification process that positivelyidentifies the vehicle were made part of this system, it could thus cutdown on vehicle theft. Alternately, thieves might attempt to disconnectthe system thereby defeating the full implementation of the system andthus increasing the danger on the roadways and defeating the RtZF™objective. The state of the system would therefore need to beself-diagnosed and system readiness must be a condition for entry ontothe restricted lanes.

11. Other Features

11.1 Incapacitated Driver

As discussed herein, the RtZF™ system of this invention also handles theproblem of the incapacitated driver thus eliminating the need for sleepsensors that appear in numerous U.S. patents. Such systems have not beenimplemented because of their poor reliability. The RtZF™ system sensesthe result of the actions of the operator, which could occur for avariety of reasons including inattentiveness cause by cell phone use,old age, drunkenness, heart attacks, drugs as well as falling asleep.

11.2 Emergencies—Car Jacking, Crime

Another enhancement that is also available is to prevent car jacking inwhich case the RtZF™ system can function like the Lojack™ system. In thecase where a car-jacking occurs, the location of the vehicle can bemonitored and if an emergency button is pushed, the location of thevehicle with the vehicle ID can be transmitted.

11.3 Headlight Dimmer

The system also solves the automatic headlight dimmer problem. Since theRtZF™ system equipped vehicle knows where all other RtZF™ systemequipped vehicles are located in its vicinity, it knows when to dim theheadlights. Since it is also interrogating the environment in front ofthe vehicle, it also knows the existence and approximate location of allnon-RtZF™ system equipped vehicles. This is one example of a futureimprovement to the system. The RtZF™ system is a system which lendsitself to continuous improvement without having to change systems on anexisting vehicle.

11.4 Rollover

It should be obvious from the above discussion that rollover accidentsshould be effectively eliminated by the RtZF™ system. In the rare casewhere one does occur, the RtZF™ system has the capability to sense thatevent since the location and orientation of the vehicle is known.

For large trucks that have varying inertial properties depending on theload that is being hauled, sensors can be placed on the vehicle thatmeasure angular and linear acceleration of a part of the vehicle. Sincethe geometry of the road is known, the inertial properties of thevehicle with load can be determined and thus the tendency of the vehicleto roll over can be determined. Since the road geometry is known thespeed of the truck can be limited based partially on its measuredinertial properties to prevent rollovers. The IMU can play a crucialrole here in that the motion of the vehicle is now accurately known to adegree previously not possible before the Kalman filter error correctionsystem was employed. This permits more precise knowledge and thus theability to predict the motion of the vehicle. The IMU can be input tothe chassis control system and, through appropriate algorithms, thethrottle, steering and brakes can be appropriately applied to prevent arollover. When the system described herein is deployed, rollovers shoulddisappear as the causes such as road ice, sharp curves and othervehicles are eliminated.

If a truck or other vehicle is driving on a known roadway where thevertical geometry (height and angle) has been previously determined andmeasured then one or more accelerometers and gyroscopes can be placed atappropriate points on the truck and used to measure the response of thevehicle to the disturbance. From the known input and measured response,the inertial properties of the vehicle can readily be determined by oneskilled in the art. Similarly, if instead of a knowledge of the roadfrom the map database, the input to the vehicle from the road can bemeasured by accelerometers and gyroscopes placed on the chassis, forexample, and then the forcing function into the truck body is known andby measuring the motion (accelerations and angular accelerations) theinertial properties once again can be determined. Finally, the inputfrom the road can be treated statistically and again the inertialproperties of the truck estimated. If a truck tractor is hauling atrailer then the measuring devices can be placed at convenient locationsof the trailer such inside the trailer adjacent to the roof at the frontand rear of the trailer.

If the map contains the information, then as the vehicle travels theroad and determines that there has been a change in the road propertiesthis fact can be communicated via telematics or other methods to the mapmaintenance personnel, for example. In this manner, the maps are keptcurrent and pothole or other evidence of road deterioration can be sentto appropriate personnel for attention.

Once the system determines that the vehicle is in danger or a rolloversituation; the operator can be notified with an audible or visualwarning (via a display or light) so that he or she can take correctiveaction. Additionally or alternately, the system can take control of thesituation and prevent the rollover through appropriate application ofbrakes (either on all wheels or selectively on particular wheels),throttle or steering.

11.5 Vehicle Enhancements

The RtZF™ system can now be used to improve the accuracy of othervehicle based instruments. The accuracy of the odometer and yaw ratesensors can be improved over time, for example, by regression, orthrough the use of a Kalman filter, against the DGPS data. The basicRtZF™ system contains an IMU which comprises three accelerometers andthree gyroscopes. This system is always being updated by the DGPSsystem, odometer, vehicle speed sensor, magnetic field and field vectorsensors, PPS and other available sensors through a Kalman filter and insome cases a neural network.

11.6 Highway Enhancements

Enhancements to the roadways that result from the use of the RtZF™system include traffic control. The timing of the stoplights can now beautomatically adjusted based on the relative traffic flow. The positionof every vehicle within the vicinity of the light can be known from thecommunication system discussed above. When all vehicles have the RtZF™system, many stoplights will no longer be necessary since the flow oftraffic through an intersection can be accurately controlled to avoidcollisions.

Since the road conditions will now be known to the system, an enhancedRtZF™ system will be able to advise an operator not to travel or,alternately, it can pick an alternate route if certain roads haveaccidents or have iced over, for example. Some people may decide notdrive if there is bad weather or congestion. The important point here isthat sensors will be available to sense the road condition as to bothtraffic and weather, this information will be available automaticallyand not require reporting from weather stations which usually have onlylate and inaccurate information. Additionally, pricing for the use ofcertain roads can be based on weather, congestion, time of day, etc.That is, pricing can by dynamically controlled.

The system lends itself to time and congestion based allocation ofhighway facilities. A variable toll can automatically be charged tovehicles based on such considerations since the vehicle can beidentified. In fact, automatic toll systems now being implemented willlikely become obsolete as will all toll booths.

Finally, it is important to recognize that the RtZF™ system is not a“sensor fusion” system. Sensor fusion is based on the theory that youcan take inputs from different sensors and combine them in such a way asto achieve more information from the combined sensors than from treatingthe sensor outputs independently in a deterministic manner. The ultimatesensor fusion system is based on artificial neural networks, sometimescombined with fuzzy logic to form a neural fuzzy system. Such systemsare probabilistic. Thus there will always be some percentage of caseswhere the decision reached by the network will be wrong. The use of suchsensor fusion, therefore, is inappropriate for the “Zero Fatalities”goal of the invention, although several of the sub-parts of the systemmay make use of neural networks.

11.7 Speed Control

Frequently a driver is proceeding down a road without knowing theallowed speed limit. This can happen if he or she recently entered aroad and a sign has not been observed or perhaps the driver just was notpaying attention or the sign was hidden from view by another vehicle. Ifthe allowed speed was represented in the map database then it could bedisplayed on an in vehicle display since the vehicle would know itslocation.

12. Summary

In sum, disclosed above is a computer controlled vehicle and obstaclelocation system and method which includes the steps of receivingcontinuously from a network of satellites on a first communication linkat one of a plurality of vehicles, GPS ranging signals for initiallyaccurately determining, in conjunction with centimeter accurate maps,the host vehicle's position on a roadway on a surface of the earth;receiving continuously at the host vehicle on a second communicationlink from a station, another vehicle or satellite, DGPS auxiliary rangecorrection signals for correcting propagation delay errors in the GPSranging signals; determining continuously at the host vehicle from theGPS, DGPS, and accurate map database signals host vehicle's position onthe surface of the earth with centimeter accuracy; communicating thehost vehicle's position to another one of the plurality of vehicles, andreceiving at the host vehicle, location information from at least one ofa plurality of other vehicles; determining whether the other vehiclerepresents a collision threat to the host vehicle based on its positionrelative to the roadway and the host vehicle and generating a warning orvehicle control signal response to control the vehicles motion laterallyor longitudinally to prevent a collision with the other vehicle. In someimplementations, the detecting step includes detecting objects byscanning with one or more cameras, radars or laser radars located on thehost vehicle. The analyzing step includes processing and analyzingdigital signals indicative of video images detected by the one or morecameras, radars or laser radars, and processing and analyzing thedigital signals using pattern recognition and range determinationalgorithms. The objects detected may include fixed or moving, or knownor unknown obstacles, people, bicycles, animals, or the like.

An optional feature of this embodiment of the invention is to operateone or more of the following systems depending on the kind of responsedetermined by the neural fuzzy logic control system: a brake pedal,accelerator pedal, steering system (e.g., steering wheel), horn, light,mirror, defogger and communication systems.

The first phase of implementation of this invention can be practicedwith only minor retrofit additions to the vehicle. These include theaddition of a differential GPS system, an inertial measurement unit(IMU) and appropriate circuitry, and an accurate map database. In thisfirst phase, the driver will only be warned when he or she is about todepart from the road surface. During the second phase of practicing thisinvention, the system will be augmented with a system that will preventthe operator from leaving the assigned corridor and in particularleaving the road at high speed. In further phases of the implementationof this invention, additional systems will be integrated which will scanthe roadway and act to prevent accidents with vehicles that do not havethe system installed. Also communication systems will be added to permitthe subject vehicle to communicate its position, velocity, etc., toother nearby vehicles that are also equipped with a system. Thiscommunication system is the main focus herein.

A primary preferred embodiment of the system, therefore, is to equip avehicle with a DGPS system, an inertial guidance system (or IMU),vehicle steering, throttle and brake control apparatus, a sub-meteraccurate digital map system with the relevant maps (or ability to accessthe relevant maps), a scanning pulsed infrared laser radar, a system forsensing or receiving signals from a highway-based precise positiondetermination system, and communications systems for (1) sending andreceiving data from similarly equipped vehicles, (2) receiving updatedmaps and map status information, and (3) receiving weather and roadcondition information. A preferred embodiment for the infrastructureenhancements includes a DGPS system, a radar reflector based, RadioFrequency Identification (RFID) based or equivalent precise positiondetermining system and local weather and road condition determinationand transmission system.

Also disclosed above are methods and apparatus for preventing vehicleaccidents. To this end, a vehicle is equipped with a differential GPS(DGPS) navigational system as well as an inertial navigation subsystem.Part of the system can be an array of infrastructure stations thatpermit the vehicle to exactly determine its position at various pointsalong its path. Such stations would typically be located at intervalssuch as every 50 miles along the roadway, or more or less frequentlydepending on requirements as described below. These stations permit thevehicle to become its own DGPS station and thus to correct for the GPSerrors and to set the position of the vehicle based initial guidancesystem. It also provides sufficient information for the vehicle to usethe carrier frequency to determine its absolute position to within a fewcentimeters or better for as long as satellite locks are maintained.Data is also available to the vehicle that provides information as tothe edges of the roadway, and edges of the lanes of the roadway, at thelocation of the vehicle so that the vehicle control system cancontinuously determine its location relative to the roadway edges and/orlane edges. In the initial implementation, the operator operates his orher vehicle and is unaware of the presence of the accident avoidancesystem. If, however, the operator falls asleep or for some other reasonattempts to drive off the roadway at high speed, the system will detectthat the vehicle is approaching an edge of the roadway and will eithersound an alarm or prevent the vehicle from leaving the roadway whendoing so would lead to an accident. In some cases, the system willautomatically reduce the speed of the vehicle and stop it on theshoulder of the roadway.

It is important to note that the invention as described in the aboveparagraph is in itself a significant improvement to automotive safety.Approximately half of all fatal accidents involve only a single vehiclethat typically leaves the roadway and impacts with a roadside obstacle,cross a yellow line or run a red light or stop sign. This typicallyhappens when the driver in under the influence of alcohol or drugs, hasa medical emergency or simply falls asleep. If this cause of accidentscould be eliminated, the potential exists for saving many thousands ofdeaths per year when all vehicles are equipped with the system of thisinvention. This would make this the single greatest advance inautomotive safety surpassing both seatbelts and airbags in lifesavingpotential.

A first improvement to this embodiment of the invention is to providethe vehicle with a means using radar, laser radar, optical or infraredimaging, or a similar technology, to determine the presence, locationand velocity of other vehicles on the roadway that are not equipped withthe accident avoidance system. The accident avoidance system (RtZF™) ofthis invention will not be able to avoid all accidents with suchvehicles for the reasons discussed above, but will be able to provide alevel of protection which is believed to surpass all known prior artsystems. Some improvement over prior art systems will result from thefact that the equipped vehicle knows the location of the roadway edges,as well as the lane boundaries, not only at the location of the equippedvehicle but also at the location of the other nearby vehicles. Thus, theequipped vehicle will be able to determine that an adjacent vehicle hasalready left its corridor and warn the driver or initiate evasiveaction. In prior art systems, the location of the roadway is not knownleading to significantly less discrimination ability.

A second improvement is to provide communication ability to other nearbysimilarly equipped vehicles permitting the continuous transmission andreception of the locations of all equipped vehicles in the vicinity.With each vehicle knowing the location, and thus the velocity, of allpotential impacting vehicles which are equipped with the RtZF,collisions between vehicles can be reduced and eventually nearlyeliminated when all vehicles are equipped with the RtZF. One suchcommunication system involves the use of spread spectrum carrier lesscommunication channels that make efficient use of the availablebandwidth and permit the simultaneous communication of many vehicles.

A third improvement comprises the addition of software to the systemthat permits vehicles on specially designated vehicle corridors for theoperator to relinquish control of the vehicle to the vehicle-basedsystem, and perhaps to a roadway computer system. This then permitsvehicles to travel at high speeds in a close packed formation therebysubstantially increasing the flow rate of vehicles on a given roadway.Naturally, in order to enter the designated corridors, a vehicle wouldbe required to be equipped with the RtZF. Similarly, this then providesan incentive to vehicle owners to have their vehicles so equipped sothat they can enter the controlled corridors and thereby shorten theirtravel time. Close packed or platooning travel is facilitated in theinvention and thus supportive of the drag reduction advantages of suchtravel. But, such travel, although it can be automatically achievedthrough implementation of the proper algorithms in a very simple manner,is not required.

Prior art systems require expensive modifications to highways to permitsuch controlled high speed close packed travel. Such modifications alsorequire a substantial infrastructure to support the system. The RtZF™ ofthe present invention, in its simplest form, does not require anymodification to the roadway but rather relies primarily on the GPS orsimilar satellite system or other precise locating system. The edge andlane boundary information is either present within the vehicle RtZF™memory or transmitted to the vehicle as it travels along the road. Thepermitted speed of travel is also communicated to the vehicles on therestricted corridor and thus each vehicle travels at the appointedspeed. Since each vehicle knows the location of all other vehicles inthe vicinity, should one vehicle slow down, due to an enginemalfunction, for example, appropriate action can be taken to avoid anaccident. Vehicles do not need to travel in groups as suggested andrequired by some prior art systems. Rather, each vehicle mayindependently enter the corridor and travel at the system defined speeduntil it leaves, which may entail notifying the system of a destination.

Another improvement involves the transmission of additional dataconcerning weather conditions, road conditions traffic accidents etc. tothe equipped vehicle so that the speed of that vehicle can be limited toa safe speed depending on road conditions, for example. If moisture ispresent on the roadway and the temperature is dropping to the point thatice might be building up on the road surface, the vehicle can benotified by the roadway information system and prevented from travelingat an unsafe speed.

In contrast to some prior art systems, with the RtZF™ system inaccordance with the invention, especially when all vehicles areappropriately equipped, automatic braking of the vehicle should rarelybe necessary and steering and throttle control should in most cases besufficient to prevent accidents. In most cases, braking means theaccident wasn't anticipated.

It is important to understand that this is a process control problem.The process is designed so that it should not fail and thus allaccidents should be eliminated. Events that are troublesome to thesystem include a deer running in front of the vehicle, a box falling offof a truck, a rock rolling onto the roadway and a catastrophic failureof a vehicle. Continuous improvement to the process is thus requiredbefore these events are substantially eliminated. Each vehicle,individual driver and vehicle control system is part of the system andupon observing that such an event has occurred, he or she should havethe option of stopping the process to prevent or mitigate an emergency.All equipped vehicles therefore have the capability of communicatingthat the process is stopped and therefore that the vehicle speed, forexample, should be substantially reduced until the vehicle has passedthe troubled spot or until the problem ceases to exist. In other words,each vehicle and each driver is part of the process. In one manner, eachvehicle is a probe vehicle.

The RtZF™ system in accordance with the invention will thus start simpleby reducing single vehicle accidents and evolve. The system has thecapability to solve the entire problem by eliminating automobileaccidents.

Furthermore, disclosed above are methods and apparatus for eliminatingaccidents by accurately determining the position of a vehicle,accurately knowing the position of the road and communicating betweenvehicles and between the vehicle and the infrastructure supportingtravel. People get into accidents when they go too fast for theconditions and when they get out of their corridor. This embodimenteliminates these and other causes of accidents. In multilane highways,this system prevents people from shifting lanes if there are othervehicles in the blind spot, thus, solving the blind spot problem. Thevehicle would always be traveling down a corridor where the width of thecorridor may be a lane or the entire road width or something in betweendepending on road conditions and the presence of other vehicles. Thisembodiment is implemented through the use of both an inertial navigationsystem (INS) and a DGPS, in some cases with carrier frequencyenhancement. Due to the fact that the signals from at least four GPS orGLONASS satellites are not always available and to errors caused bymultiple path reception from a given satellite, the DGPS systems cannotbe totally relied upon. Therefore the INS is a critical part of thesystem. This will improve as more satellites are launched and additionalground stations are added. It will also significantly improve when theWAAS and LAAS systems are implemented and refined to work with landvehicles as well as airplanes. It will also be improved with theimplementation of PPS.

Also disclosed above is a method for transferring information between avehicle and a transmitter which comprises the steps of transmitting aunique pseudorandom noise signal by the transmitter in a carrier-lessfashion composed of frequencies within a pre-selected band, encodinginformation in the noise or pseudo-noise signal relating to anidentification of the transmitter and a position of the transmitter andproviding the vehicle with means for extracting the information from thenoise or pseudo-noise signal. The code to use for encoding the noise orpseudo-noise signal may be selected based on the position of thetransmitter so that analysis of the code, or a portion thereof, providesan indication of the position of the transmitter. Information aboutaccidents, weather conditions, road conditions, map data and trafficcontrol devices and about errors in a GPS signal can also be encoded inthe noise or pseudo-noise signals. The information may be encoded in thenoise or pseudo-noise signal in various ways, including but not limitedto phase modulation of distance or time between code transmissions,phase or amplitude modulation of the code sequences, changes of thepolarity of the entire code sequence or the individual code segments, orbandwidth modulation of the code sequence. The information may beencoded in the noise or pseudo-noise signal sequentially from generalinformation to specific information about the position of thetransmitter, e.g., from the country in which the transmitter ispositioned to the actual square meter in which the transmitter islocated. The transmitter may be arranged in a moving object such as avehicle to provide vehicle-to-vehicle communications, in which case, thevelocity and optionally direction of travel of the vehicle is alsoencoded in the noise or pseudo-noise signal, or at a fixed location. Inthe latter case, the location can be used to correct GPS signals. Inthis regard, the information encoded in the noise or pseudo-noise signalmay be the GPS coordinate location of the transmitter.

In a related arrangement, an antenna is arranged on the vehicle toreceive noise or pseudo-noise signals and a processor is coupled to theantenna. The processor may be constructed or programmed to analyze thereceived noise or pseudo-noise signals in order to determine whether anyreceived noise or pseudo-noise signals originate from transmitterswithin a pre-determined distance from the vehicle. Such analysis can bebased on an initial portion of the noise or pseudo-noise signals, i.e.,the processor can scan through multiple the noise or pseudo-noisesignals reading only the initial part of each to assess which noise orpseudo-noise signal(s) is/are particularly important and then obtain andprocess only those of interest.

While the invention has been illustrated and described in detail in thedrawings and the foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiments have been shown and described and thatall changes and modifications that come within the spirit of theinvention are desired to be protected.

This application is one in a series of applications covering safety andother systems for vehicles and other uses. The disclosure herein goesbeyond that needed to support the claims of the particular inventionthat is claimed herein. This is not to be construed that the inventorsare thereby releasing the unclaimed disclosure and subject matter intothe public domain. Rather, it is intended that patent applications havebeen or will be filed to cover all of the subject matter disclosedabove.

1. A method for obtaining information about objects in the environmentoutside of and around a vehicle, comprising: directing a laser beam fromthe vehicle into the environment; receiving from an object in the pathof the laser beam a reflection of the laser beam at a location on thevehicle; forming at least one image from the received laser beamreflections; and analyzing the at least one image formed from thereceived laser beam reflections to obtain information about the objectfrom which the laser beam is being reflected, the analyzing stepcomprising range gating the received laser beam reflections to limitanalysis of the at least one image formed from the received laser beamreflections to only images formed from laser beam reflections receivedfrom an object within a defined range such that objects at distanceswithin the range are isolated from surrounding objects.
 2. The method ofclaim 1, wherein the analyzing step obtains information about thedistance between the vehicle and the object.
 3. The method of claim 1,wherein the laser beam is infrared.
 4. The method of claim 1, furthercomprising controlling the direction of the laser beam.
 5. The method ofclaim 1, further comprising: providing a digital map includinginformation relating to roads on which the vehicle can travel or istraveling; and defining a field into which the laser beam will bedirected based on the map; the step of directing the laser beam into theenvironment comprising directing the laser beam into the defined field.6. The method of claim 1, further comprising: scanning with the laserbeam at a high scanning speed; and scanning with an additional laserbeam at a slower scanning speed.
 7. The method of claim 1, wherein theanalyzing step further comprises analyzing the at least one image formedfrom the received laser beam reflections to detect the presence ofobjects potentially affecting operation of the vehicle, the range gatingstep being performed once the presence of each object is detected andthe range being determined to encompass any objects whose presence hasbeen detected.
 8. The method of claim 7, wherein the analyzing stepfurther comprises narrowing the range such that laser beam reflectionsfrom only the object whose presence is detected and other objects in thesame range are analyzed.
 9. The method of claim 7, wherein the analysisof the at least one image formed from the received laser beamreflections to detect the presence of objects is performed using apattern recognition algorithm.
 10. The method of claim 7, wherein theanalyzing step further comprises ascertaining the identity of oridentifying each object and proceeding to obtain information about thedistance between the object and the vehicle based on the identity oridentification of the object.
 11. The method of claim 1, furthercomprising alerting a driver of the vehicle if the information obtainedabout an object in the environment outside of and around the vehicleindicates that a collision with the object is about to occur.
 12. Themethod of claim 1, wherein the laser beam reflections are received by animage sensor which forms the at least one image.
 13. A method foravoiding collisions between a vehicle and another object, comprising:mounting a laser beam projector on the vehicle; directing a laser beamfrom the projector outward from the vehicle; determining whether anobject is present in the path of the laser beam based on reception ofreflections of the laser beam caused by the presence of the object inthe path of the laser beam; when an object is determined to be present,setting a distance range including a distance between the vehicle andthe object; processing only received reflections of the laser beamemanating from objects in the set distance range to determine whethereach object may impact the vehicle; and if a determination is made thatthe object may impact the vehicle, effecting a countermeasure with aview toward preventing the impact.
 14. The method of claim 13, furthercomprising: providing a digital map including information relating toroads on which the vehicle can travel or is traveling; and defining afield into which the laser beam will be directed based on the map; thestep of directing the laser beam outward from the vehicle comprisingdirecting the laser beam into the defined field.
 15. The method of claim13, further comprising: scanning with the laser beam at a high scanningspeed; and scanning with an additional laser beam at a slower scanningspeed.
 16. The method of claim 13, wherein the processing step comprisesapplying a pattern recognition technique to ascertain the identity of oridentify each object in the set distance range and assessing thepotential for and consequences of an impact between the vehicle and theobject based on the identity or identification of the object.
 17. Themethod of claim 13, wherein the countermeasure effected entails alertinga driver of the vehicle about the possible impact and/or altering thetravel of the vehicle.
 18. A system for avoiding collisions between avehicle and another object, comprising: a laser beam projector arrangedon the vehicle to direct a laser beam outward from the vehicle; areceiving unit for receiving reflections of the laser beam which reflectoff of objects in the path of the laser beam; and a processor coupled tosaid receiving unit and arranged to process any received reflections todetermine whether an object is present in the path of the laser beam andwhen an object is determined to be present, said processor beingarranged to set a distance range including a distance between thevehicle and the object, process only received reflections of the laserbeam emanating from objects in the set distance range to determinewhether each object may impact the vehicle, and if a determination ismade that the object may impact the vehicle, cause a countermeasure tobe effected with a view toward preventing the impact.
 19. The system ofclaim 18, wherein said processor includes a pattern recognitionalgorithm which ascertains the identity of or identifies each object inthe set distance range and assesses the potential for and consequencesof an impact between the vehicle and the object based on the identity oridentification of the object.
 20. The system of claim 18, furthercomprising a driver notification system or a vehicle control system, thecountermeasure caused by said processor being activation of said drivernotification system to alert the driver of the impending impact oractivation of said vehicle control system to vary the travel of thevehicle to avoid the impending impact.
 21. A method for obtaininginformation about objects in the environment outside of and around avehicle, comprising: providing a digital map including informationrelating to roads on which the vehicle can travel or is traveling;defining a field in the environment into which a laser beam will bedirected based on the map; directing a laser beam from the vehicle intothe defined field; receiving from an object in the path of the laserbeam a reflection of the laser beam at a location on the vehicle; andanalyzing the received laser beam reflections to obtain informationabout the object from which the laser beam is being reflected, theanalyzing step comprising range gating the received laser beamreflections to limit analysis of the received laser beam reflections toonly those received from an object within a defined range such thatobjects at distances within the range are isolated from surroundingobjects.
 22. A method for obtaining information about objects in theenvironment outside of and around a vehicle, comprising: directing twolaser beams from the vehicle into the environment; receiving from anobject in the path of the laser beams a reflection of the laser beams ata location on the vehicle; and analyzing the received laser beamreflections to obtain information about the object from which the laserbeam is being reflected, the directing step comprising scanning with afirst one of the laser beams at a high scanning speed and scanning witha second one of the laser beams at a slower scanning speed, theanalyzing step comprising range gating the received laser beamreflections to limit analysis of the received laser beam reflections toonly those received from an object within a defined range such thatobjects at distances within the range are isolated from surroundingobjects.
 23. A method for obtaining information about objects in theenvironment outside of and around a vehicle, comprising: directing alaser beam from the vehicle into the environment; receiving from anobject in the path of the laser beam a reflection of the laser beam at alocation on the vehicle; and analyzing the received laser beamreflections to obtain information about the object from which the laserbeam is being reflected, the analyzing step comprising analyzing thereceived laser beam reflections to detect the presence of objectspotentially affecting operation of the vehicle and range gating thereceived laser beam reflections to limit analysis of the received laserbeam reflections to only those received from an object within a definedrange such that objects at distances within the range are isolated fromsurrounding objects, the range gating step being performed once thepresence of each object is detected and the range being determined toencompass any objects whose presence has been detected.
 24. The methodof claim 23, wherein the analyzing step further comprises narrowing therange such that laser beam reflections from only the object whosepresence is detected and other objects in the same range are analyzed.25. The method of claim 23, wherein analysis of the received laser beamreflections to detect the presence of objects is performed using apattern recognition algorithm.
 26. The method of claim 23, wherein theanalyzing step further comprises ascertaining the identity of oridentifying each object and proceeding to obtain information about thedistance between the object and the vehicle based on the identity oridentification of the object.